How to convert square feet to cubic yards
Square feet measure area and cubic yards measure volume, so you need a depth. Multiply the area by the depth in feet, then divide by 27.
The formula
Cubic yards = square feet × depth (ft) ÷ 27
Worked example
500 square feet at 3 inches deep (0.25 feet) is 125 cubic feet, or 4.63 cubic yards.
How to use this calculator
Enter the area in square feet and the depth of the material. The calculator converts square feet to cubic yards by multiplying the two and dividing by 27, because one cubic yard holds 27 cubic feet. If you do not know the area yet, measure the length and width in feet and multiply them.
A shortcut when the depth is in inches
Depth is usually measured in inches, so you can skip the conversion to feet with this version of the formula:
Cubic yards = square feet × depth (inches) ÷ 324
The 324 is 27 × 12. For the example above, 500 × 3 ÷ 324 = 4.63 cubic yards, the same answer.
More examples
The table shows the same 500 square feet at several depths.
| Depth | Cubic feet | Cubic yards |
|---|---|---|
| 1 inch | 41.67 | 1.54 |
| 2 inches | 83.33 | 3.09 |
| 3 inches | 125 | 4.63 |
| 4 inches | 166.67 | 6.17 |
| 6 inches | 250 | 9.26 |
A larger area works the same way. 1,200 square feet at 2 inches deep is 200 cubic feet, or 7.41 cubic yards.
Areas with more than one depth
Split the job into parts, convert each part and add the results. For example, 300 square feet at 4 inches is 3.70 cubic yards and 200 square feet at 2 inches is 1.23 cubic yards, for a total of 4.93 cubic yards.
Converting to bags
Bagged material is usually labeled in cubic feet. Multiply cubic yards by 27 to get cubic feet, then divide by the bag size and round up. The 4.63 cubic yards above is 125 cubic feet. If a bag holds 2 cubic feet, that is 62.5, so you would buy 63 bags.
What changes the result
- Depth. Volume rises in step with depth. Going from 2 inches to 4 inches doubles the cubic yards.
- Area. Doubling the area also doubles the volume.
- Uneven ground. Low spots take more material than the average depth suggests, so measure the depth in several places.
What the result means
The answer is the volume of material that fills the area to the depth you entered. Bulk suppliers sell by the cubic yard, so this is the number to give them. Ask what increments they deliver and round up, because running short usually costs more than a small surplus. For 4.63 cubic yards, that might mean ordering 5.
Common mistakes
- Leaving the depth in inches. 500 × 3 ÷ 27 gives 55.6, which is 12 times too much.
- Dividing by 9 or by 3 instead of 27. Nine converts square feet to square yards, not to cubic yards.
- Using one depth for a whole area when part of it is deeper.
- Ordering the bare number with no margin. Loose material such as mulch and soil settles after it is spread.
- Guessing the area. A small error in length or width is multiplied through the whole calculation.
Related calculators
For slabs, footings and bag counts, use the concrete calculator. To find the area of a room or yard first, use the square footage calculator. If you need flat area in yards rather than volume, see square feet to square yards.
Frequently asked questions
How do I convert inches to feet?
Divide by 12.
How much does one cubic yard cover?
About 324 square feet at 1 inch deep, 108 at 3 inches and 81 at 4 inches.
What is this used for?
Ordering concrete, mulch, gravel and topsoil.
Can I convert square feet to cubic yards without a depth?
No. Square feet describe a flat surface and cubic yards describe a volume. Without a depth there is nothing to convert.
How many cubic feet are in a cubic yard?
27. A cubic yard is 3 feet long, 3 feet wide and 3 feet high, and 3 × 3 × 3 = 27.
How many square feet does a cubic yard cover at 2 inches or 6 inches deep?
About 162 square feet at 2 inches and 54 square feet at 6 inches. Divide 324 by the depth in inches.
How do I measure an area that is not a rectangle?
Split it into rectangles, work out the square feet of each and add them together. Then convert the total using the depth.