Mulch and Bark Calculator

This calculator works out how much mulch or bark you need to cover a garden in New Zealand, in both cubic metres for bulk orders and bags for smaller jobs, so you spread the right depth without running short or over-ordering. Mulch is one of the most useful things you can do for a garden, suppressing weeds, holding moisture in the soil through dry spells, and tidying up the look of beds, but the amount needed surprises people because a thin-looking layer over a decent-sized bed adds up to a lot of material. The volume is simply the area you are covering times the depth of mulch, and from there you can express it as cubic metres for a bulk delivery or convert to litres and divide by the bag size to count bags. You enter the garden area, the depth in millimetres, and the size of bag you would buy, and the calculator returns the volume in cubic metres and the number of bags. A depth of around fifty to seventy-five millimetres is right for most beds, enough to do the job without smothering plants, and you should keep mulch clear of stems and trunks. Bulk is usually cheaper per litre for large areas, while bags suit small jobs. An estimate to plan your order.

Aim for 50 to 75 mm depth on beds. Bulk is usually cheaper per litre; bags suit small jobs. An estimate for planning only.