How do I work out the area of several rooms?

Calculate the area of each room, then add them together. For identical areas, enter the size once and set the quantity. For different room sizes, total them up separately.

How much extra should I allow for flooring or paint?

For flooring and tiling, add about 5 to 10% for cuts and waste. For paint, divide the area by the coverage rate on the tin (often around 10 to 14 square metres per litre per coat) and remember you usually need two coats.

Square Metre Calculator

Work out the area of a room, wall, or section in square metres. Enter the length and width, choose metres or centimetres, and add a quantity if you have several identical areas. The calculator shows the area per space and the total in square metres, which is what you need for flooring, tiling, paint, turf, and rates of all kinds.

Length

Width

Units

Number of areas

20 m²

total area

Per area20 m²

Number of areas1

How to calculate square metres

Area in square metres is length times width, with both measured in metres. If you measured in centimetres, multiply the two figures and divide by 10,000, because there are 10,000 square centimetres in a square metre. For several identical areas, work out one and multiply by the quantity.

Worked example

A lounge is 5 m long and 4 m wide. The area is 5 x 4, which is 20 square metres. If you were carpeting three rooms of that exact size, the total is 60 square metres.

For carpet or tiles, add about 10% for cuts and offcuts, so 60 square metres becomes about 66 square metres ordered.

Using the area for materials

Flooring and tiles: add 5 to 10% for waste and cuts.
Paint: divide the wall area by the tin's coverage (often 10 to 14 m² per litre per coat), and allow for two coats.
Turf or seed: use the area directly, then follow the product's coverage rate.

Frequently asked questions

How many square centimetres in a square metre?

10,000. So divide an area measured in square centimetres by 10,000 to get square metres.

How do I handle an L-shaped room?

Split it into rectangles, work out each rectangle, and add them together.

Related calculators

Area Conversion Calculator: convert between area units.
Cubic Metre Calculator: volume in cubic metres.
Concrete Calculator: concrete volume and bags.
Unit Converter: convert length, area, and more.

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