Soil and mulch calculator

Calculate the volume of potting soil, compost or mulch needed to cover a flower bed or vegetable garden based on its area and the depth you want, plus the number of bags to buy. Calculated locally, in your browser.

Example:
5-8 cm for standard mulch, 15-20 cm for a new soil bed.

How it works

Estimating the volume of soil or mulch yourself keeps you from buying too many bags (waste) or too few (extra trips to the garden center). The calculation multiplies the area to cover by the desired depth to get a volume, then divides that volume by the capacity of one bag to find how many bags to buy.

What mulch depth should I choose?

For standard maintenance mulching in a vegetable garden or an established bed, a depth of 5 to 8 cm (2 to 3 inches) is generally enough to limit weed growth and retain soil moisture. For a new bed where you want to enrich the soil deeply with potting soil, aiming for 15 to 20 cm (6 to 8 inches) is common.

Why is the estimated weight approximate?

Density varies a lot depending on the material (a wood-chip mulch is much lighter than enriched soil or compost) and on its moisture content at the time of purchase. The weight shown is an indicative estimate; refer to the weight printed on your product's packaging for a precise calculation.

Nothing you enter here is sent to a server: the calculation stays local to your browser.