Multiply the three dimensions, then divide by 27
Measure length and width in feet and depth in feet too. Depth is usually given in inches, so divide it by 12 first. A 10 ft × 12 ft slab poured 4 inches deep is 10 × 12 × 0.333 = 40 cubic feet, which is 40 ÷ 27 = 1.48 cubic yards. The 27 comes from a cubic yard being 3 ft on every side.
Coverage per cubic yard by depth
One cubic yard spreads over very different areas depending on how thick you lay it. Divide 324 by the depth in inches to get the square feet covered.
| Depth | Area covered | Typical use |
|---|---|---|
| 1 inch | 324 sq ft | sand, thin topdressing |
| 2 inches | 162 sq ft | compost, light mulch |
| 3 inches | 108 sq ft | mulch (standard bed) |
| 4 inches | 81 sq ft | soil, gravel base |
| 6 inches | 54 sq ft | fill, deep topsoil |
Handy rule: one cubic yard covers about 100 sq ft at 3 inches deep.
What a cubic yard weighs, by material
Volume tells you what to order; weight tells you what the truck is hauling and what delivery costs. Moisture can swing these by 20 to 30%.
| Material | Per cubic yard | Tons |
|---|---|---|
| Concrete (wet) | 4,050 lb | 2.03 |
| Gravel (dry) | 2,835 lb | 1.42 |
| Topsoil | 2,200 lb | 1.10 |
| Wet clay soil | 3,000 lb | 1.50 |
| Wood mulch | 590 lb | 0.30 |
Wet gravel weighs about 20% more than dry. Add 5 to 10% for mulch and 10 to 15% for gravel to cover settling and waste.
Common questions
How do I convert cubic feet to cubic yards?
Divide the cubic feet by 27, because a cubic yard is 3 ft x 3 ft x 3 ft. For example, 54 cubic feet is 2 cubic yards.
How many square feet does a cubic yard cover?
It depends on depth. At 3 inches deep one cubic yard covers about 108 square feet; at 2 inches about 162; at 4 inches about 81. The rule is 324 divided by the depth in inches equals the square feet covered.
How many bags equal one cubic yard?
Nine bags of 3 cubic feet each, or 13.5 bags of 2 cubic feet each, since a cubic yard is 27 cubic feet.
