Topsoil Calculator
Enter the size of your lawn, garden or raised bed and the depth of soil to see how many cubic yards, tons and bags of topsoil you need. Soil weight is editable because moisture and soil type change it.
How to use this topsoil calculator
- Measure the length and width of the area to be covered and pick feet or meters.
- Enter the depth of topsoil you want to spread, in inches or centimeters.
- Keep the 10 percent extra for settling or change it to suit your project.
- Check the soil weight and the bag size. Both are editable defaults, so use the figures from your supplier and the bag label if they differ.
- Press Calculate. Use Copy result to paste the numbers into a shopping list, or Export CSV to keep a record.
How to calculate how much topsoil you need
Topsoil is sold by volume (cubic yards or bags) and sometimes by weight. The calculator finds the volume of a flat layer and then converts it.
- Cubic feet = length (ft) x width (ft) x depth (in) / 12 x (1 + extra % / 100)
- Cubic yards = cubic feet / 27
- Tons = cubic yards x tons per cubic yard
- Bags = cubic feet / bag size, rounded up
For a round bed, work out the area first with the Square Footage Calculator, then use the equivalent length and width that gives that area.
Worked example
You are filling a raised bed that is 8 ft long and 4 ft wide with 10 inches of soil. Depth in feet = 10 / 12 = 0.8333 ft. Volume = 8 x 4 x 0.8333 = 26.67 cubic feet. With 10% extra: 29.33 cubic feet = 1.09 cubic yards. At 1.1 tons per cubic yard that is about 1.20 tons. In 0.75 cubic foot bags you need 29.33 / 0.75 = 39.1, so 40 bags.
For bulk delivery, 1.09 cubic yards would usually be ordered as 1.25 or 1.5 yards, depending on what your supplier offers.
Assumptions & limits
- The area is flat and the depth is even. Sloped ground and mounds need to be split up.
- The default soil weight of 1.1 tons per cubic yard is only a starting point. Wet, compacted or clay soil can weigh more, so use your supplier figure.
- The default bag size is a placeholder. Bags are sold in different sizes, so enter the size on the label.
- The extra percentage is not a standard. Soil can settle after watering.
- This is a maths tool. Ask a garden centre or landscaper about the right soil mix and depth for your plants.
Frequently asked questions
How do I calculate cubic yards of topsoil?
Multiply length by width in feet, multiply by the depth in feet (inches divided by 12), and divide by 27. A 10 ft by 10 ft area at 4 inches deep is 33.3 cubic feet, or 1.23 cubic yards.
How many bags of topsoil do I need?
Divide the cubic feet you need by the cubic feet in one bag and round up. A 0.75 cubic foot bag covers 0.75 sq ft at 12 inches deep, or 9 sq ft at 1 inch deep.
How deep should topsoil be?
It depends on what you are planting and what is already there. Lawns, beds and raised planters differ, so check the advice for your plants or ask a local garden centre.
Does topsoil settle?
Loose soil can settle after watering and rain, which is why the calculator starts with an extra 10 percent that you can change.
Is topsoil sold by weight or volume?
Both are used. Bagged soil is sold by volume, and bulk soil may be sold by the cubic yard or by the ton. The calculator shows both.
Can I use metric units?
Yes. Choose meters for length and width and centimeters for depth. Results are still shown in US units.
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Last updated: November 2026