Topsoil Calculator
Estimate topsoil for lawns and garden beds in cubic meters or cubic yards, with kilograms, tonnes, US tons and adjustable waste and bulk density.
Add 5–10% for waste and uneven ground; default 10%.
Default bulk density: 1,300 kg/m³. Moisture, organic content and screening cause large variations; bagged soil mixes may be much lighter.
About the Topsoil Calculator
Topsoil quantities are useful when establishing lawn areas, filling shallow garden beds or improving planting zones. Measure the area to cover and the added soil depth, not the full excavation depth unless you intend to fill it completely. Exclude existing soil you plan to retain, and calculate separate sections when the depth varies.
The default bulk density is 1,300 kg/m³, but a moist mineral soil and a light compost-rich blend can weigh very differently. A 4 m by 3 m bed topped up by 10 cm needs 1.2 m³ before allowance. With 10% extra, the estimate is 1.32 m³ and 1,716 kg at the default density. This allowance does not predict long-term settling precisely.
Select meters or centimeters independently in metric mode, or feet and inches in imperial mode. The volume conversion uses one cubic yard = 0.764554857984 cubic meters; weight uses your chosen density. Keep soil separate from protective coverings estimated by the Mulch Calculator. For adjoining pathways, compare the Gravel Calculator and Sand Calculator rather than using topsoil weight assumptions for aggregate.
Frequently Asked Questions
Why is topsoil weight only an estimate?
Moisture, organic matter, particle size and packing affect bulk density. Ask your supplier for the density of the specific blend being delivered.
Should I add extra for settling?
A 5–10% planning allowance can cover modest losses or settling, but the required amount varies. Avoid assuming the percentage replaces the supplier's guidance.
Does this calculate the soil already in my garden?
It calculates the rectangular volume you enter. Enter only the new layer depth when estimating a top-up, and split uneven areas into separate sections.
Take this calculation further
Browse the other calculators collection for more tools in this subject.
For a related calculation, use Paver/Patio Base Calculator to estimate construction gravel sub-base and sand bedding together using independent layer depths and metric or imperial units. Alternatively, use Sand Calculator to estimate construction sand volume and weight with metric or imperial dimensions and waste allowance.