Mulch, Soil and Gravel Calculator
How many cubic yards, cubic metres or bags of mulch, soil, gravel or sand to buy.
Good to know. A cubic yard is 27 cubic feet, about 14 bags of mulch. Past a few yards, a delivery costs less.
Approximate. Real-world values vary.
How it works
In plain words
The volume is the area times the depth, with the depth turned into the same unit as the area: centimetres into metres, or inches into feet. A cubic yard is 27 cubic feet. Bags are the volume divided by the bag size, rounded up. The weight uses a typical density for the material.
The formula
volume = length × width × depth cubic yards = cubic feet ÷ 27 bags = volume ÷ bag size, rounded up 1 cubic foot = 28.32 litres
Worked example
A 6 × 3 m bed with 7.5 cm of mulch: 18 m² × 0.075 m = 1.35 m³, or 27 bags of 50 litres.
Sources
- Typical loose densities published by landscape suppliers About 1.4 US tons a cubic yard for gravel, 1.35 for sand, 1.1 for topsoil and 0.3 for bark mulch.
- NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B Exact conversion factors for US customary units.
Sources checked September 29, 2026. 6 automated tests check its answers on every change.
About the mulch, soil and gravel calculator
Mulch, soil, gravel and sand are sold by volume: by the cubic yard in the US, by the cubic metre or the bulk bag elsewhere, and in small bags at garden centres. Measure the area, choose how deep the layer should be, and the calculator works out the volume and the number of bags.
The usual mistake is the depth. It is measured in centimetres or inches while the bed is in metres or feet, and 3 inches is a quarter of a foot, not 3. A 10 × 10 ft bed 3 inches deep holds 25 cubic feet, a little under a cubic yard.
Typical depths: 5–8 cm (2–3 in) of mulch keeps weeds down without smothering roots; more is not better. Gravel paths need about 5 cm (2 in) over a firm base, driveways more. A new raised bed or lawn needs 10–15 cm (4–6 in) of topsoil.
Stone and sand are heavy: a cubic yard of gravel weighs about 1.4 tons, and a cubic metre about 1.7 tonnes, which is more than most car trailers and small pickups can carry. Bulk deliveries are cheaper per cubic yard than bags once you need more than a few.
Questions people ask
How much mulch do I need?
Multiply the area by the depth. A 10 × 10 ft bed 3 inches deep needs 25 cubic feet: about 0.93 cubic yards, or 13 bags of 2 cubic feet.
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so 13.5 bags of 2 cubic feet: buy 14.
How much does a cubic yard of gravel weigh?
About 1.4 US tons (2,800 lb), depending on the stone and how wet it is. A cubic metre weighs about 1.6–1.7 tonnes.
How deep should mulch be?
2–3 inches (5–8 cm). Deeper mulch can starve roots of air; keep it clear of stems and tree trunks.