How much soil you need
Measure the area and decide how deep the new soil will be. The calculator does the rest:
Length × width × depth (in feet) = cubic feet. Divide by 27 for cubic yards, or by the bag size for bags.
A 10 × 6 foot bed with 6 inches of topsoil needs 30 cubic feet: 15 bags of 2 cubic feet, or about 1.1 cubic yards in bulk. For a circular bed, choose the circle shape. It measures the full circle, including any empty center.
How deep
| Job | Guidance | Depth to enter |
|---|---|---|
| New lawn | University of Illinois Extension: aim for 6 inches or more of well-prepared soil | 6 in or more |
| Raising a bed or filling a low spot | Measure from the current surface to where you want the new surface | your measurement |
| Raised beds | Use the raised bed soil calculator | fill depth |
The lawn guidance refers to the whole prepared soil profile, including soil already there. Enter only the depth of material you plan to add; you do not automatically need 6 inches of new topsoil.
For an area with uneven depth, measure in a few places and use the average.
Mixing in compost
University of Maryland Extension suggests improving compacted, clay-heavy soil by adding compost and purchased topsoil in a 1:2 or 1:1 ratio. Enter the compost share under Compost in the mix: about 33% for 1:2, or 50% for 1:1. The calculator splits the total into soil and compost and rounds each up to whole bags. See the compost calculator for spreading compost on its own.
Buying topsoil
Topsoil should be dark and crumbly with an earthy smell. University of Maryland Extension suggests asking the seller for soil test results and where the soil came from. Bulk soil is sold by the cubic yard or cubic meter, with suppliers’ own increments and minimums; bags list their volume in cubic feet or litres.
Keep your plan
Print your current plan or choose Save as PDF in the browser’s print dialog. Your inputs stay in a device draft when browser storage is available. An optional free account lets you save and sync the project in My projects. Calculating and printing stay open to everyone.
Read the measurement guide for the meaning of these quantities and worked examples.