The formula
Cubic yards = square yards × depth (in) ÷ 36
Why 36? A yard is 36 inches. If your depth were a full yard, one square yard would hold exactly one cubic yard. Your depth is a slice of that yard, so you divide it by 36 to see what fraction you have.
Say you have 20 square yards of lawn to cover with 3 inches of topsoil. That is 20 × 3 ÷ 36 = 1.67 cubic yards. Order a little more, because ground is never flat.
Cubic yards by area and depth
| Square yards | 2 in | 3 in | 4 in | 6 in |
|---|---|---|---|---|
| 1 | 0.06 | 0.08 | 0.11 | 0.17 |
| 5 | 0.28 | 0.42 | 0.56 | 0.83 |
| 10 | 0.56 | 0.83 | 1.11 | 1.67 |
| 25 | 1.39 | 2.08 | 2.78 | 4.17 |
| 50 | 2.78 | 4.17 | 5.56 | 8.33 |
| 100 | 5.56 | 8.33 | 11.11 | 16.67 |
Need a number that is not in the table? Every row scales. If 10 square yards at 4 inches is 1.11 cubic yards, then 30 square yards is three times that.
The other direction: how far does a yard go?
Suppliers sell by the cubic yard, so you often want to know how much ground one yard covers. Divide 36 by the depth in inches.
| Depth | Square yards covered by 1 cubic yard | Square feet |
|---|---|---|
| 1 in | 36.0 | 324 |
| 2 in | 18.0 | 162 |
| 3 in | 12.0 | 108 |
| 4 in | 9.0 | 81 |
| 6 in | 6.0 | 54 |
| 8 in | 4.5 | 40 |
| 12 in | 3.0 | 27 |
So a cubic yard spread 3 inches deep covers 12 square yards, which is 108 square feet. That is a rule of thumb you can use at the supplier's yard when you're guessing what to put in the truck.
If your measurements are in feet
Most people measure a space in feet and then get stuck. Divide square feet by 9 to get square yards, then use the formula above. Or skip a step and use the square feet to cubic yards calculator, which takes feet, yards or meters and a depth in inches, feet or centimeters.
For odd shapes, circles and triangles, see how to calculate cubic yards. The cubic yard conversion chart covers cubic feet, meters and gallons.
Frequently asked questions
How do you convert square yards to cubic yards?
Multiply the square yards by the depth in inches and divide by 36. You can't do it without a depth.
How many square yards does a cubic yard cover?
At 3 inches deep, 12 square yards. Divide 36 by the depth in inches for any other depth.
How many cubic yards in 10 square yards at 4 inches?
10 x 4 / 36 = 1.11 cubic yards.
How do I get square yards from square feet?
Divide by 9, because a square yard is 3 feet by 3 feet.