Topsoil calculator

Topsoil calculator: how much topsoil do you need?

Multiply the area in square feet by the depth in inches and divide by 12 for cubic feet; divide by 27 for cubic yards. A 30 by 20 foot area at 4 inches deep needs 7.41 cubic yards of topsoil, before any extra for settling. Enter your own area and depth below to get cubic yards, cubic feet and bags, and add your supplier’s weight and price to get tons and cost. It works the same for garden soil, compost and fill dirt.

How to measure for topsoil

1. Measure the area. Length times width for a rectangle; split odd shapes into rectangles, circles and triangles and add them up.
2. Decide the depth. In inches. Your supplier or local extension service can say what suits your project and soil.
3. Work out the volume. Square feet × inches ÷ 12 = cubic feet; ÷ 27 = cubic yards.
4. Add extra for settling. Loose soil settles once it is spread and watered.
5. Order by the yard, or count bags. For bags, divide the cubic feet by the volume printed on the bag.

Measuring for something other than soil, or working in meters? Use the cubic yard calculator; for stone and driveways, the gravel calculator; for sand, the sand calculator; for mulch, the mulch calculator.

Frequently asked questions

How do I calculate how much topsoil I need?

Multiply the area in square feet by the depth in inches, then divide by 12 to get cubic feet. Divide cubic feet by 27 to get cubic yards. A 30 by 20 foot area is 600 square feet; at 4 inches deep that is 600 × 4 ÷ 12 = 200 cubic feet, or 200 ÷ 27 = 7.41 cubic yards. Add a little extra for settling.

How many cubic feet are in a cubic yard?

27. A cubic yard is 3 feet by 3 feet by 3 feet, so divide cubic feet by 27 to get cubic yards, or multiply cubic yards by 27 to get cubic feet.

How many bags of topsoil make a cubic yard?

Divide 27 by the bag's volume in cubic feet, printed on the bag. Bags of 0.75 cubic feet take 36 to make a cubic yard, 1 cubic foot bags take 27, 1.5 cubic foot bags take 18 and 2 cubic foot bags take 13.5. Bags sold by weight usually list a volume too; use that.

How much does a cubic yard of topsoil weigh?

It depends on the blend and especially on how wet it is: wet soil is much heavier than dry. Ask your supplier what a yard of that product weighs, enter it in the calculator, and it converts your yards to tons. That number also matters for what a truck or trailer can carry.

Should I order extra topsoil?

Loose topsoil settles after it is spread and watered, and ground is rarely perfectly level, so most people order a bit more than the exact volume. The calculator adds whatever percentage you choose.

Does this work for garden soil, compost or fill dirt?

Yes. Volume is volume: the cubic yards are the same for topsoil, garden soil, compost, fill dirt, mulch or sand. Only the weight per yard and the price change, and the calculator takes those from you.

How do I measure an odd-shaped area?

Split it into rectangles, circles and triangles, work out each one, and add the square feet together; then enter the total as 'I know the square feet'. A circle is 3.1416 × radius × radius; a triangle is base × height ÷ 2.

How deep should topsoil be?

That depends on what you are growing and what is underneath. Check with your local extension service or your supplier for your soil and climate, then use the depth table to see what each extra inch adds.