Home, garden and building jobs questions, answered

Board-on-Board Fence Calculator

What is a board-on-board fence?

A board-on-board fence (also called a shadow board or good-neighbour fence) has vertical boards alternating on either side of the horizontal rails. Each board overlaps the gap left by the boards on the opposite side, giving privacy from both sides while allowing some airflow. Because boards appear on both faces, the fence looks the same from the front or the back, which is why it is sometimes called a good-neighbour fence.

How do I calculate how many boards I need for a board-on-board fence?

The centre-to-centre spacing between boards on the same side equals 2 x (board width minus overlap), because a board on the opposite side fills the gap and overlaps each neighbour by the overlap amount. Divide the fence length by this spacing and round up to get the boards per side, then double it for the total across both sides. For example, a 10-metre fence using 150 mm-wide boards with a 25 mm overlap has a same-side board spacing of 2 x (150 - 25) = 250 mm. Boards per side = ceil(10000 / 250) = 40. Total boards = 40 x 2 = 80.

How much overlap should a board-on-board fence have?

A typical overlap for a board-on-board fence is 25 to 40 mm. A 25 mm overlap on a 150 mm board leaves a 250 mm spacing between board centres on each side, with boards alternating on the two faces every 125 mm. Larger overlaps give more privacy but use more timber. Too little overlap (under about 20 mm) can leave gaps visible at an angle. For full privacy with no visible gap, aim for at least 30 mm of overlap per side.

Brick Calculator

How many bricks per square metre?

A standard brick wall uses about 50 bricks per square metre for a single skin, including the mortar joints. The exact number depends on the brick size and joint thickness. The calculator lets you set the bricks per square metre to match.

How many bricks do I need?

Multiply the wall area by the bricks per square metre, then add a waste allowance for cuts and breakages, usually around 5 to 10%. The calculator works this out from the area you enter.

How do I work out wall area?

Multiply the wall length by its height. Subtract any large openings such as doors and windows if you want a tighter figure. Enter the net wall area and the calculator handles the rest.

Carpet Calculator NZ

How do I measure a room for carpet?

Measure the length and the width of the room at their widest points and multiply them for the floor area. Add a waste allowance because carpet comes in fixed width rolls and needs trimming, and seams have to line up. The calculator adds the allowance for you.

Why is there waste with carpet?

Carpet is made in set roll widths, usually 3.66 metres, so cutting a room to fit almost always leaves offcuts. Hallways, stairs, and pattern matching add more. A 10% allowance is a sensible starting point, but your installer will measure exactly.

Does the price include underlay and fitting?

This calculator costs the carpet only, from the price per square metre you enter. Underlay, smoothedge, delivery, and installation are usually extra, so ask for a full quote that includes them.

Carpet and Flooring Area Calculator NZ

How do I measure a room for flooring?

Measure the length and width at the widest points and multiply them for the floor area in square metres. For L-shaped rooms, split into rectangles and add the areas. Always add a waste allowance for cuts and joins.

How much waste should I allow?

A waste allowance of around 5 to 10 percent is common for tiles and planks, and more for carpet or patterned flooring where rolls and pattern matching create offcuts. Awkward shapes and diagonal lays need more.

Is carpet sold by the square metre?

Carpet usually comes in fixed-width rolls, so the way it is cut affects how much you need, often more than the bare floor area. Use this area plus waste as a starting point and confirm with the retailer based on roll width.

Curtain Fabric Calculator NZ

How much fabric do I need for curtains?

Multiply the track width by a fullness ratio to get the total flat width, divide by the fabric width to find how many widths you need, then multiply the widths by the drop plus an allowance for hems and heading.

What is fullness?

Fullness is how gathered the curtains are. A ratio of about 2 means the fabric is twice the track width, giving a nicely full look. Sheer fabrics often use more, around 2.5 to 3, while a flat blind uses close to 1.

Why add a hem allowance?

Each drop needs extra fabric turned under at the top for the heading and at the bottom for the hem, typically a combined allowance of around 20 to 30 centimetres. Patterned fabric needs more again to match the pattern across widths.

Deck & Fence Cost Calculator NZ 2026

How much does a deck cost per square metre in NZ?

As a guide, a ground-level treated pine deck is often $350 to $500 a square metre supply and installed, while hardwood, composite or elevated decks with balustrades can exceed $700. Use a rate that matches your materials and site, then add extras and a contingency.

How much does a fence cost per metre in NZ?

A basic timber paling fence is commonly $150 to $300 a lineal metre, depending on height, materials and access. Retaining, gates, and rocky or sloping ground push the rate up, so price your specific job rather than relying on an average.

Why include a contingency?

Outdoor builds frequently uncover surprises such as poor ground, services to avoid, or extra materials. A contingency of around 10 to 15 percent gives you a buffer so a small problem does not blow the budget, and anything left over is a bonus.

Deck Joist Spacing Calculator NZ 2026

What spacing should deck joists be in NZ?

Timber decking is commonly fixed to joists at 400mm or 450mm centres, but the correct spacing depends on the decking board, its thickness and direction, and the span. Always check the decking manufacturer's guidance and the NZS 3604 span tables before building.

Why is there one more joist than gaps?

A deck needs a joist at both ends of the run as well as the ones in between, so the joist count is always the number of spaces plus one. Forgetting the final joist is a common reason people come up one short.

Does closer joist spacing cost much more?

Going from 450mm to 400mm centres adds joists and lineal metres, raising timber cost, but it stiffens the deck and is sometimes required for thinner or composite boards. This calculator lets you compare both spacings before you order.

Deck Stain Calculator NZ

How much deck stain do I need per square metre?

Most oil-based deck stains cover 8 to 12 square metres per litre per coat on smooth, previously coated timber. Rough sawn or new untreated timber is more absorbent and can drop coverage to 4 to 6 square metres per litre. Always check the coverage rate printed on the tin you plan to use, since products vary. Two coats are standard for new or bare timber, and one maintenance coat is often enough for a deck that already has a sound coating.

Do I need to allow extra for wastage when calculating deck stain?

Yes. A waste allowance of around 10 percent is standard practice to cover uneven application, spillage, absorbent end grain, and touch-ups. Deck boards also have far more surface area than a flat floor plan suggests once you account for the gaps between boards and the edges, so builders often add a further allowance for board edges on gap-decking.

How many coats of stain does a deck need?

New or bare timber typically needs two coats to get adequate film build and UV protection. A deck that is being recoated as maintenance, and still has most of its existing coating intact, often only needs one coat. Manufacturers such as Resene, Cabot's and Intergrain publish specific recoat guidance for their products, so check the data sheet for your chosen stain.

Decking Calculator NZ

How many decking boards do I need?

Divide the deck width by the board width plus the gap between boards to get the number of rows. Multiply by the deck length for the total lineal metres of decking. The calculator does this and also estimates the joists.

What gap should I leave between deck boards?

A gap of around 3 to 5 mm is common so water drains and the timber can move. Hardwoods and wet timber are laid tighter because they shrink as they dry. Set the gap to match your boards and conditions.

How far apart should joists be?

Joist spacing is usually 400 to 450 mm for timber decking, and sometimes less for thin or composite boards. Always follow the board manufacturer's span tables and the building code. The calculator uses the spacing you enter.

Electric Fence Energiser Calculator NZ

How do I size an electric fence energiser?

Start from the total length of electrified wire rather than the length of the fence line, because a fence line carrying three live wires is three times the load of one carrying a single wire. Then compare that against what the manufacturer of your energiser says it will drive. Ratings are given in joules and manufacturers state their own kilometre figures, which is why this page asks for yours rather than supplying one: the same joule rating is quoted against very different lengths by different makers.

Why is my electric fence not holding stock?

Usually load rather than the energiser being faulty. Vegetation touching live wires drains power continuously, and so do cracked insulators, a wire touching a batten or a steel standard, and poor earthing. An energiser that was comfortable in winter can be badly overloaded by spring growth on the same fence. Earthing is the most commonly undersized part of the whole system and the cheapest to fix.

How much headroom should an energiser have?

Enough to cope with growth on the wires and with whatever you are likely to add. A system running at its rated limit on a clean fence in winter has nothing left for spring, and extending a fence later means replacing the energiser rather than adding wire. Sizing on the manufacturer's figure for fence under load, rather than the headline clean fence figure, is the usual way to build that margin in.

Farm Fencing Materials Calculator NZ

How many posts do I need for a farm fence?

Divide the fence length by your post spacing and add one, because a fence with ten bays has eleven posts. Post spacing on New Zealand farm fences commonly runs from 4 to 6 metres for a conventional post and batten fence and wider again on an electric fence, so the spacing you choose changes the count more than the length does. Strainer posts at the ends and corners are counted separately here, since they take the strain of the wire and are a different, heavier item.

How long is a coil of fencing wire?

It depends on the gauge, because coils are sold by weight rather than length. A 25 kilogram coil of 2.5 millimetre high tensile wire runs to roughly 650 metres, which follows from the wire's cross section and the density of steel rather than from any standard. Thicker wire from the same weight of coil gives you less length. Use the length printed on your coil if it has one, because galvanising and manufacturing tolerance both move the figure.

How many battens go in a fence bay?

Three battens per bay is a common starting point on a conventional sheep and cattle fence, giving effective spacing of about 1.25 metres on a 5 metre bay. More battens hold the wire spacings truer and matter most where you are fencing for sheep or lambs; fewer are used where the fence is mainly for cattle or is electrified. Batten count is a choice about how well the fence holds its shape, not a rule.

Farm Lease Rate Calculator NZ

How are farm leases quoted in New Zealand?

Three ways, and they are not interchangeable. Dollars per hectare a year is the most common on a whole farm lease. Dollars per stock unit is used where the country varies in quality, because it prices the carrying capacity rather than the area. And a return on land value expresses the lease as a percentage yield, which is how an owner tends to look at it. The same lease can be quoted any of the three ways, so converting between them is usually the first step in comparing two offers.

Why does per stock unit matter more than per hectare?

Because a hectare is not a unit of production. Steep hill country and flat river terrace both measure a hectare but carry very different numbers of stock, so a lease that looks dear per hectare can be cheap per stock unit and the other way round. Pricing per stock unit compares what the country will actually run, which is what the lessee is buying. Per hectare is easier to quote and is what most advertisements use.

What return do farm leases give an owner?

Expressed as a percentage of land value it is usually low compared with other income assets, because farmland returns come partly as capital growth rather than entirely as income. That is why an owner comparing a lease with a term deposit is not comparing like with like. This page gives you the yield figure from your own numbers rather than a market rate, since lease rates differ enormously by district, land class and the term and conditions of the lease itself.

Fence Palings Calculator NZ 2026

How many palings do I need per metre?

With 100mm palings and a 10mm gap, you need about 9 palings per metre per side. Butting them with no gap needs about 10 per metre. Wider palings or larger gaps reduce the count, which this calculator adjusts for automatically.

Should I clad one side or both?

Cladding one side is cheaper and common for boundary fences. Both sides, or an alternating both-sides design, looks tidy from each property and is sometimes required by a shared-fence agreement. Cladding both sides roughly doubles the paling count.

What else do I need besides palings?

A fence also needs posts set in concrete, horizontal rails, and fixings such as nails or screws, plus any capping. This calculator covers palings only, so use it alongside a full fencing calculator and a post-hole concrete calculator for the complete materials list.

Fence Palings Count Calculator NZ

How do I calculate how many fence palings I need?

Divide the total fence length by the spacing between paling centres (paling width plus gap). Round up to the nearest whole number. For example, a 20-metre fence with 75 mm wide palings and a 5 mm gap uses 80 mm centres, giving ceil(20,000 / 80) = 250 palings. Always add at least 10% for wastage, offcuts, and errors, giving 275 palings to purchase.

What gap should I leave between fence palings?

A 5 mm gap is standard for privacy fences using treated pine palings. This allows for timber expansion in wet weather without the palings buckling. For a more open look, a 10 to 20 mm gap is common. Overlapping palings (used on lapped-and-capped styles) have no gap and instead overlap by 10 to 20 mm, which is entered as a negative gap in this calculator.

How many rails does a fence need?

Most NZ residential fences up to 1.8 m high use two horizontal rails (top and bottom). Fences 1.8 m to 2.1 m high typically use three rails for added rigidity. Fences over 2.1 m, or those in exposed or high-wind locations, should use three or four rails. Rails are typically H4-treated 100x50 mm timber, and the total rail length equals the fence length multiplied by the number of rails.

Gravel and Aggregate Calculator NZ

How much gravel do I need?

Multiply the area to cover by the depth of gravel to get the volume in cubic metres, then multiply by the density to convert to tonnes, since gravel is usually sold by the cubic metre or tonne. A typical driveway gravel is around 1.5 tonnes per cubic metre.

What depth of gravel should I lay?

For a path, 50 to 75 millimetres is common; for a driveway, 100 to 150 millimetres over a compacted base. Deeper layers need more material, so getting the depth right matters as much as the area.

Is gravel sold by tonne or cubic metre?

Suppliers sell both, so it helps to know your need in each. This tool gives cubic metres and tonnes using the density you enter. Different aggregates have different densities, so check with your supplier for an exact figure.

Gravel Calculator NZ

How much gravel do I need?

Multiply the area by the depth to get the volume in cubic metres, then multiply by the density to get tonnes. Gravel is usually around 1.5 tonnes per cubic metre. The calculator works out both from the area and depth you enter.

How deep should gravel be?

A path is often 50 mm deep, while a driveway is usually 75 to 100 mm or more over a compacted base. Deeper layers need more material. Enter the depth in millimetres for your job.

How many tonnes in a cubic metre of gravel?

Most gravel and crushed metal weighs about 1.5 tonnes per cubic metre, though it varies with the stone and how wet it is. The calculator lets you change the density if your supplier gives a different figure.

Knock-Down Rebuild vs Renovate Calculator NZ

Is it cheaper to renovate or rebuild?

Renovating is usually cheaper up front, but a knock-down rebuild gives a brand new home that can be worth much more and cost less to run and maintain. The right answer depends on your existing home's condition and the end value each path delivers.

What costs go into a knock-down rebuild?

Demolition and disposal, then the full new build cost, plus consents, services and design. You keep the land, so you are buying a new house on a section you already own.

When does renovating make more sense?

When the existing structure is sound, the layout works, and you can get the result you want for less than a rebuild. If the home needs gutting, has serious issues, or you want a very different house, a rebuild often wins on end value.

Lawn Care Cost Calculator NZ

Is it cheaper to mow my own lawn or hire a contractor?

Mowing yourself is usually cheaper in cash once you own a mower, since you only pay for fuel and upkeep. A contractor costs more per visit but saves your time. Whether it is worth it depends on what your time is worth to you.

How do I compare the two over a season?

Count the mows in a season, then compare the contractor's price per visit with your own fuel and upkeep cost. This calculator also values your time, so you can see the true comparison, not just the cash.

Should I value my time in the comparison?

It helps. If you would happily spend the time, the cash cost is what matters. If your time is scarce or you dislike the job, valuing your hours shows whether paying a contractor is good value for you.

Lawn Seed Quantity Calculator NZ

How much grass seed do I need?

Multiply your lawn area in square metres by the sowing rate in grams per square metre. A new lawn typically needs around 35 to 50 grams per square metre, while over-sowing an existing lawn uses about half that.

What is the difference between new and over-sowing rates?

A bare new lawn needs the full rate to establish good coverage, often 35 to 50 grams per square metre. Over-sowing, where you thicken an existing lawn, uses a lighter rate of around 15 to 25 grams, since the grass is already partly there.

When should I sow grass seed in New Zealand?

Spring and early autumn are best, when the soil is warm and moisture is reliable, giving seed the conditions to germinate and establish before extremes of heat or cold. Avoid sowing in the middle of summer or winter.

Lawn Seed Quantity Calculator NZ

How much grass seed do I need per square metre in New Zealand?

The seeding rate depends on the grass type. For a standard ryegrass and fescue mix (the most common lawn seed in New Zealand), the recommended rate is 25 to 40 grams per square metre for a new lawn. Fine fescue lawns use 15 to 25 g/m2 because the seed is small and germination rates are high. Tall fescue requires 35 to 45 g/m2. Overseeding an existing lawn uses roughly half these rates. Always add a 10 to 15 percent wastage buffer to account for seed that does not germinate, is blown by wind, or is eaten by birds.

What is the difference between sowing a new lawn and overseeding?

Sowing a new lawn involves preparing bare or stripped soil and applying seed at the full recommended rate, typically 25 to 40 g/m2 for ryegrass mixes. Overseeding (also called oversowing) is applied to an existing thin or patchy lawn to thicken it up. Because the established grass provides some ground cover and competition, you use approximately half the new-lawn seeding rate, around 15 to 20 g/m2 for a ryegrass mix. The calculator includes a toggle for both scenarios.

How do I measure my lawn area for seeding?

For a rectangular lawn, multiply the length by the width in metres to get area in square metres (m2). For an L-shaped or irregular lawn, break it into rectangles, calculate each, and add them together. For a roughly circular lawn, measure the radius (half the diameter) and use the formula pi x radius squared (approximately 3.14 x r x r). You can also use the satellite view in Google Maps to measure an area by right-clicking and selecting 'Measure distance' to trace the boundary.

Mulch and Bark Calculator NZ

How much mulch do I need?

Multiply the area to cover by the depth of mulch to get the volume in cubic metres. Bagged mulch is sold in litres, so divide the volume in litres by the bag size to find the number of bags, or order bulk by the cubic metre.

How deep should mulch be?

A layer of around 50 to 75 millimetres is usual for garden beds, deep enough to suppress weeds and hold moisture without smothering plants. Keep mulch clear of plant stems and tree trunks to prevent rot.

Is it cheaper to buy bulk or bags?

Bulk mulch by the cubic metre is usually cheaper per litre than bags for larger areas, but bags are easier to handle and store for small jobs. This tool gives both the cubic metres and the number of bags so you can compare.

Mulch Calculator NZ

How much mulch do I need?

Multiply the garden area by the depth of mulch to get the volume in cubic metres, then divide by the bag size if you are buying bags. The calculator does both. Bagged mulch is often sold in 40 to 60 litre bags.

How deep should mulch be?

A layer of about 50 to 75 mm is usual for suppressing weeds and holding moisture, kept clear of plant stems. Thinner layers break down and need topping up sooner. Enter your chosen depth in millimetres.

How many litres in a cubic metre?

There are 1,000 litres in a cubic metre. So a 50 litre bag is 0.05 of a cubic metre, and it takes 20 of those bags to make one cubic metre. Bulk mulch by the cubic metre is usually cheaper for large areas.

Paint Calculator NZ

How much paint do I need?

Multiply your wall area by the number of coats, then divide by the coverage of the paint, usually around 10 square metres per litre. Most walls need two coats, and bare or dark surfaces may need more. The calculator turns that into litres and cans.

How do I measure wall area?

Add up the length of all the walls and multiply by the height. You can subtract large windows and doors, roughly 1.5 to 2 square metres each, if you want a tighter estimate. For a quick result, enter the total wall area you measured.

How many coats of paint?

Two coats is standard for a good finish over an existing painted surface. New plasterboard usually needs a sealer or undercoat first, and strong colour changes can need an extra coat. Set the number of coats to match your job.

Paint Coverage Calculator NZ

How much paint do I need?

Multiply the area by the number of coats, then divide by the paint's coverage per litre, usually around 10 to 12 square metres per litre. This calculator does it and tells you the litres and the number of standard cans, with a margin to round up.

How many coats should I apply?

Two coats are standard for a durable, even finish. You may need more when painting a light colour over a dark one, or onto bare, porous or patchy surfaces, which also reduce how far each litre goes, so allow extra paint in those cases.

Should I subtract windows and doors?

You can, for a more precise figure, by deducting the area of large openings. Many people leave them in as a built-in margin for touch-ups and waste. Either way, rounding up to the next whole can is sensible so you do not run short.

Paint Quantity Calculator NZ

How much paint do I need?

Multiply the wall area by the number of coats, then divide by the coverage per litre stated on the paint. Most wall paints cover around 10 to 12 square metres per litre per coat, though porous or dark-over-light surfaces need more.

How many coats should I apply?

Two coats is standard for a durable, even finish. Bare or patchy surfaces, or a big colour change, may need a primer or sealer coat first, which is an extra coat to include in your quantity.

Should I subtract doors and windows?

For a rough estimate you can paint the full wall area, which builds in a small buffer. For a tighter figure, subtract large openings like windows and doors. Either way, buying a little extra avoids running out mid-job.

Plasterboard Calculator NZ

How many sheets of plasterboard do I need?

Work out the wall and ceiling area, then divide by the area of one sheet and add a waste allowance for cuts around windows, doors, and corners. The calculator does this from the room size and sheet size you enter.

What size are plasterboard sheets in NZ?

Common sizes are 2.4 by 1.2 metres, which is 2.88 square metres, and longer 3.0 or 3.6 metre sheets. Longer sheets mean fewer joints. The calculator lets you set the sheet size you are using.

Should I include the ceiling?

If you are lining the ceiling as well, include it. The calculator adds the ceiling area, which is the room length times the width, to the wall area. Untick the ceiling option if you only need the walls.

Raised Garden Bed Soil Calculator NZ

How much soil do I need for a raised bed?

Multiply the bed length, width and depth to get the volume. In metres that gives cubic metres; multiplying by 1,000 gives litres, which is how bagged soil and compost are sold, so divide by the bag size for the number of bags.

What should I fill a raised bed with?

A blend of garden mix or topsoil with compost works well, sometimes with coarser material at the bottom of deep beds to save mix and aid drainage. Beds settle over time, so it is fine to slightly overfill at the start.

Is bulk soil cheaper than bags?

For larger beds, bulk garden mix by the cubic metre is usually cheaper per litre than bags, though bags are convenient for one small bed. This tool gives both cubic metres and bags so you can compare.

Renovate vs Move House Calculator NZ

Is it cheaper to renovate or move?

Renovating is often cheaper once you count the cost of moving, because selling and buying carries agent commission, legal fees and moving costs, plus the extra you pay for a better home. But moving can give you a different location or layout a renovation cannot.

What does it cost to move house?

The transaction costs of moving include real estate agent commission on the sale, legal fees on both the sale and purchase, and removal costs, on top of the higher price of the home you move to. These add up to a large sum that buys you no extra house.

When does moving make more sense?

When you need a different location, school zone or section that renovating cannot deliver, or when your home cannot practically be extended to suit. If you just need more space and the home allows it, renovating often wins on cost.

Renovation Cost Per Room Calculator NZ 2026

How much does it cost to renovate a kitchen or bathroom in NZ?

Kitchens and bathrooms are the most expensive rooms because of plumbing, electrical, waterproofing and cabinetry. A standard kitchen often starts around $25,000 and a bathroom around $20,000, with budget jobs less and premium fit-outs considerably more.

What does the quality level change?

The quality level scales the base cost: a budget renovation uses stock fittings and finishes and costs less, while a premium one uses custom joinery, stone and designer fixtures and costs much more in the same room. The multiplier reflects that range.

Why include a contingency for renovations?

Opening up walls, floors and ceilings often reveals rot, old wiring, leaks or non-compliant work that must be fixed. A contingency of around 10 to 20 percent protects your budget from these surprises, which are very common in older New Zealand homes.

Renovation Value Uplift Calculator NZ

Will my renovation add more value than it costs?

Some renovations add more than they cost, such as a tidy kitchen or bathroom update or adding a bedroom, while others add less than they cost and are really lifestyle choices. Comparing the expected value added with the cost shows which yours is.

How do I estimate the value a renovation adds?

A local agent or recent comparable sales are the best guide to what a particular improvement adds in your area. Enter that expected uplift here against your cost to see the return and whether the project stacks up financially.

Does over-capitalising matter?

Yes. Spending more than the local market will pay back, known as over-capitalising, is common with high-end renovations in modest areas. This tool flags when your cost is well above the value it is likely to add.

Roof Pitch Calculator

What is roof pitch?

Roof pitch is how steep a roof is. It is described as a rise over a run, such as 3 in 12, meaning the roof rises 3 units for every 12 horizontal. It can also be given as an angle in degrees, which this calculator works out from the rise and run.

How do I calculate rafter length?

The rafter is the sloping side of the right triangle formed by the rise and the run. By Pythagoras, it is the square root of the rise squared plus the run squared. The calculator gives the rafter length for the rise and run you enter.

What is a low pitch roof?

A low or shallow pitch is generally under about 15 degrees, and needs roofing designed for it so water drains properly. Steeper roofs shed water and debris more easily. Always follow the roofing manufacturer's minimum pitch.

Soil & Fill Truckloads Calculator NZ 2026

How many cubic metres in a truckload of soil?

It depends on the truck. A small tipper carries about 3 cubic metres, a standard tip truck around 6, and a truck and trailer up to 12 cubic metres or more. Choose your truck size here to convert the volume you need into whole loads.

Why allow for compaction?

Loose soil, fill and bark settle once they are spread and compacted, so the finished depth ends up lower than the loose material you tipped. Adding a compaction allowance of around 10 to 20 percent means you order enough to reach your target level.

Is it cheaper to buy bulk or bagged?

For anything beyond a small garden bed, bulk delivery by the cubic metre is much cheaper per unit than bags, though you pay cartage per load. This calculator helps you size the order so you are not paying for a second delivery or a wasted pile.

Tile Adhesive & Grout Calculator NZ 2026

How much tile adhesive do I need per square metre?

For standard tiles with a notched trowel, around 3 to 5 kilograms per square metre is typical, while large-format tiles needing a thicker bed use more. This calculator uses the coverage rate you enter, so set it to match your adhesive and trowel.

How is grout quantity calculated?

Grout depends on tile size, thickness and joint width. The standard formula multiplies the sum of the tile length and width by the joint width, the thickness and the grout density, then divides by the tile area. Small tiles and wide joints use much more grout.

Should I buy extra adhesive and grout?

Yes. Coverage varies with how flat the substrate is, the trowel technique and offcuts, so buy a little more than the calculated amount. Running short mid-job risks a colour or batch mismatch and delays while the first tiles set.

Tile Calculator

How many tiles do I need?

Divide the area you are tiling by the area of one tile, then add a waste allowance for cuts and breakages. The calculator does this for you once you enter the area and the tile size, and a typical waste allowance is 10%.

How much waste should I allow?

Around 10% is normal for a simple layout. Allow more, up to 15% or 20%, for diagonal patterns, lots of cuts, or large format tiles, and keep a few spares for future repairs.

How do I work out the tile size in square metres?

Multiply the tile width by its height in metres. A 300 by 300 mm tile is 0.3 by 0.3, which is 0.09 square metres, so it takes about 11 tiles to cover a square metre. The calculator handles this from the millimetre sizes you enter.

Tile Count Calculator NZ

How many tiles do I need?

Divide the area you are tiling by the area of one tile, then add a waste allowance for cuts and breakages. Work in the same units, and round up to whole tiles, ideally to whole boxes since tiles are usually sold by the box.

How much waste should I allow for tiling?

Around 10 percent is typical for a straight lay, more for diagonal or patterned layouts, large-format tiles, or rooms with lots of cuts around fixtures. Keep a few spare tiles after the job for future repairs.

Are tiles sold by the box?

Usually, with a set number of tiles or square metres per box. Once you know the tiles needed, round up to whole boxes, and buying from the same batch ensures a consistent colour and finish across the job.

Board Feet Calculator NZ 2026

What is a board foot?

A board foot is a volume of timber one foot long, one foot wide and one inch thick. It is the standard unit for pricing hardwood and rough-sawn timber in many countries. This calculator converts your metric dimensions into board feet and back to cubic and lineal metres.

How do I convert board feet to metric?

This calculator does it automatically. It converts millimetres to inches and metres to feet to compute board feet, and also gives the cubic metres and lineal metres New Zealand timber is usually sold in, so you can compare prices in either system.

Should I use nominal or dressed size?

Board feet are usually based on the nominal or rough-sawn size, which is larger than the final dressed (planed) size. Use the size that matches how the timber is being measured and priced, and confirm with the supplier which dimension a quote refers to.

Timber Board Feet and Lengths Calculator

What is a board foot of timber?

A board foot (BF) is a unit of timber volume equal to a piece that is 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches or approximately 2,360 cubic centimetres). The formula is: Board Feet = (Thickness in inches x Width in inches x Length in feet) divided by 12. Board feet measure the volume of rough or dressed timber and are commonly used to price hardwoods and large softwood orders in New Zealand and internationally. Lineal metres (LM) measure only the length, regardless of cross-section, and are used for ordering standard-sized framing, decking, and cladding.

How do I convert millimetres to inches for board feet?

To convert millimetres to inches, divide by 25.4 (since 1 inch = 25.4 mm). For example, a piece 50 mm thick is 50 / 25.4 = 1.969 inches, which is commonly called 2 inches or 50 mm dressed. To convert metres to feet, multiply by 3.28084 (since 1 metre = 3.28084 feet). This calculator accepts both metric (mm for thickness and width, metres for length) and imperial (inches for thickness and width, feet for length) inputs and converts automatically.

How many lineal metres are in a board foot?

Board feet and lineal metres measure different things, so the conversion depends on the cross-section of the timber. A lineal metre of 50 x 150 mm (approximately 2 x 6 inch) timber contains approximately 3.18 board feet (since 1 metre = 3.2808 feet, and (50/25.4) x (150/25.4) x 3.2808 / 12 = 3.18 BF). For ordering standard dressed framing timber, lineal metres are the most common unit in New Zealand. Board feet are more common when ordering hardwoods, rough-sawn timber, or importing.

Turf Calculator NZ

How much turf do I need?

Measure the lawn area in square metres and add a waste allowance for shaping around curves and edges. Divide by the area of one roll if your turf is sold by the roll. The calculator works out both the area and the rolls.

What size is a roll of turf?

Ready lawn is often sold by the square metre, or in rolls and slabs around 1 square metre each. Sizes vary by supplier, so set the roll size to match what you are buying.

How much waste should I allow for turf?

Around 5 to 10% covers trimming to fit curved edges and garden beds. Lay turf as soon as possible after delivery and water it well, especially in the first couple of weeks.

Wallpaper Calculator

How many rolls of wallpaper do I need?

Work out the wall area by multiplying the perimeter of the room by the height, then divide by the usable area of one roll, allowing for waste from pattern matching and trimming. The calculator does this from the measurements and roll size you enter.

What size is a roll of wallpaper?

A standard roll is about 10 metres long and 0.53 metres wide, covering roughly 5 square metres. Patterned papers waste more because each strip must line up, so the usable coverage is lower than the full roll area.

Should I buy extra wallpaper?

Yes. Always round up to whole rolls and buy a little spare, ideally from the same batch so the colour matches. Large pattern repeats need a bigger allowance, so increase the waste percentage for those.

Wallpaper Rolls Calculator NZ

How many wallpaper rolls do I need?

Divide the wall perimeter by the roll width to find the number of drops, work out how many full drops you get from a roll given the wall height plus pattern repeat, then divide the drops by the drops per roll and round up.

Why does the pattern repeat matter?

With a patterned wallpaper, each drop has to be cut to align the pattern with its neighbour, which wastes some length at the top of each drop. A larger repeat means more waste, so it reduces how many usable drops you get from a roll.

Should I subtract doors and windows?

For a straightforward estimate, use the full perimeter, which builds in a buffer. You can deduct very large openings, but it is wise to keep the extra in case of mistakes, and to buy all rolls from the same batch for a consistent pattern.