VolunaroShort answer: multiply the length, the width and the depth, all in feet, and divide by 27. A 10 × 10 ft space filled 6 in deep is 10 × 10 × 0.5 = 50 cubic feet, which is 50 ÷ 27 = 1.85 cubic yards.
For your own measurements, use the cubic yard calculator. Read on to check the steps, use the depth table or handle round shapes.
The formula, step by step
- Area in square feet. Length × width for a rectangle. If the shape is irregular, find its area first with the square footage calculator.
- Depth in feet. Inches ÷ 12. Six inches is 0.5 ft.
- Volume in cubic feet. Area × depth in feet.
- Cubic yards. Cubic feet ÷ 27, because a yard is 3 feet and 3 × 3 × 3 = 27.
Worked example: a 10 × 10 ft space, 6 in deep
| Step | Calculation | Result |
|---|---|---|
| Area | 10 ft × 10 ft | 100 ft² |
| Depth | 6 in ÷ 12 | 0.5 ft |
| Volume | 100 ft² × 0.5 ft | 50 ft³ |
| Cubic yards | 50 ÷ 27 | 1.85 yd³ |
Quick reference: cubic yards per 100 square feet
Scale these by your area divided by 100. They come from the same formula, with no margin.
| Depth | Cubic feet | Cubic yards |
|---|---|---|
| 2 in | 16.7 | 0.62 |
| 3 in | 25.0 | 0.93 |
| 4 in | 33.3 | 1.23 |
| 6 in | 50.0 | 1.85 |
| 12 in | 100.0 | 3.70 |
One cubic yard covers 108 square feet at 3 in deep, because 108 × 0.25 = 27 cubic feet.
A round column or hole
A round shape is a cylinder: π × radius × radius × depth. A column 2 ft across and 3 ft deep has a radius of 1 ft, so its volume is π × 1 × 1 × 3 = 9.42 cubic feet, or 0.35 cubic yards.
Adding a margin
The formula gives the volume of the space. Compaction, settling and spillage change how much you need to order, and the right margin depends on the material and the supplier. The calculator has an optional margin field. If you add 10 percent to the 1.85 cubic yards above, you get 2.04.
Converting to other units
- Cubic yards to cubic feet: multiply by 27.
- Cubic yards to cubic meters: multiply by 0.7646. This follows from a yard being exactly 0.9144 m, as listed in the NIST conversion factors under Sources.
- Cubic meters to cubic yards: multiply by 1.308.
Common mistakes
- Using inches as feet. Entering 6 instead of 0.5 makes the answer twelve times too big.
- Dividing by 9 or 3. A cubic yard is 27 cubic feet, not 9.
- Forgetting the hole. Subtract anything that will not be filled.
- Skipping the unit change. Cubic yards are a volume. Tons and bags need the density or the bag size of your material.
What this guide cannot tell you
- How much weighs what. For crushed stone, concrete or mulch, use the gravel calculator, the concrete calculator or the mulch calculator.
- The right margin for your job. Ask your supplier.
The calculator gives planning estimates. Our assumptions are listed on the methodology page.
Frequently asked questions
What is the formula for cubic yards?
Length × width × depth, all in feet, divided by 27. If the depth is in inches, divide it by 12 first.
How many cubic feet are in a cubic yard?
27, because a yard is 3 feet and 3 × 3 × 3 = 27.
How many cubic yards do I need for 100 square feet at 3 inches deep?
About 0.93 cubic yards: 100 × 0.25 ÷ 27 = 0.926.
Does this tell me how many tons or bags I need?
No. Cubic yards measure volume only. Weight depends on the material and bags on the size printed on the label, so use the calculator for that material.