Mulch Calculator NZ

This calculator works out how much mulch or bark you need to cover a garden bed, so you can order the right amount instead of guessing and running short or paying for surplus. You enter the garden area in square metres, the depth of mulch you want in millimetres, and the bag size in litres if you plan to buy bagged mulch rather than bulk. It multiplies the area by the depth to get the volume in cubic metres, converts that to litres, then divides by your chosen bag size to show how many bags to buy, rounding up so you never fall short. The results update instantly as you type: the total volume needed in cubic metres, the number of bags at your chosen size, and the equivalent volume in litres. Most gardens are mulched to a depth of 50 to 75 mm, deep enough to suppress weeds and hold moisture without smothering plants, so try that range if you are unsure. For larger areas, ordering mulch in bulk by the cubic metre is usually cheaper than buying many small bags, so use the cubic metre figure to compare bulk pricing against the bagged cost. Bag sizes and mulch density vary between suppliers, and settling over time can slightly reduce coverage, so treat the result as a solid guide and round up a little when ordering.

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