Cubic Yard Calculator
Enter a rectangle or a circle and a depth to get the volume in cubic yards, cubic feet and cubic meters. It works for any bulk material, with an optional allowance for settling.
Quick answer: An area 12 ft × 10 ft filled 3 in deep is 30 cubic feet, or 1.11 cubic yards, and 1.22 yd³ with a 10% allowance.
Cubic yards = length (ft) × width (ft) × depth (ft) ÷ 27. If the depth is in inches, divide it by 12 first. One cubic yard is 3 ft × 3 ft × 3 ft, exactly 27 cubic feet.
Example: an area 12 ft × 10 ft and 3 in deep is 12 × 10 × 0.25 = 30 ft³, or 1.11 yd³. With a 10% allowance it is 1.22 yd³.
Method
How this calculator works
This is the volume step behind nearly every bulk order. It has no density or price built in, so it works for concrete, gravel, soil, sand and mulch alike.
Footprint area
Choose a rectangle or a circle. For a circle, enter the diameter, the distance straight across. Lengths accept feet and inches, like 12 ft 6 in.
Rectangle: Area (ft²) = Length (ft) × Width (ft)Circle: Area (ft²) = π × (Diameter (ft) ÷ 2)²Multiply by the depth
Depth is usually quoted in inches, so divide by 12 to get feet before you multiply. Plain numbers in the depth field are inches (centimeters in metric), and you can also type 1 ft or 2 ft 6 in.
Volume (ft³) = Area (ft²) × Depth (in) ÷ 12Cubic feet to cubic yards
NIST Handbook 44 defines 1 cubic yard as 27 cubic feet, which is 46,656 cubic inches or 0.764554857984 cubic meters. One cubic foot is 0.028316846592 cubic meters.
Cubic yards = Volume (ft³) ÷ 27Cubic meters = Volume (ft³) × 0.028316846592Optional allowance
The allowance starts at 0% so you see the exact volume. Add a percentage if the material settles, compacts or spills, or if you cannot go back for more. Your call, from 0 to 25%.
Volume with allowance = Volume × (1 + Allowance ÷ 100)Worked example: 12 ft × 10 ft, 3 in deep
Arithmetic checked| Step | Math | Result |
|---|---|---|
| Area of the footprint | 12 × 10 | 120 ft² |
| Depth in feet | 3 in ÷ 12 | 0.25 ft |
| Volume in cubic feet | 120 × 0.25 | 30 ft³ |
| Convert to cubic yards | 30 ÷ 27 | 1.1111 yd³ |
| Convert to cubic meters | 30 × 0.028316846592 | 0.8495 m³ |
| Optional: add a 10% allowance | 1.1111 × 1.10 | 1.2222 yd³ |
| Total volume (no allowance) | 1.11 yd³ | |
Square feet to cubic yards works the same way: 500 ft² at 3 in deep is 500 × 0.25 = 125 ft³, and 125 ÷ 27 = 4.63 yd³.
Disclaimer
Results are planning estimates based on the dimensions and assumptions you enter. They are not engineering, structural or building-code advice. Product yields, densities and coverage vary by manufacturer, batch and site conditions. Check product labels, your supplier and your local building department before you order materials or start work. Read the full calculation disclaimer.
Accuracy
What affects your estimate
The calculator returns volume, which is exact. Whether that volume is what you should order depends on the material.
Settling and compaction
Gravel, fill and soil compact once spread, and mulch settles. If you need the finished layer at a certain depth, add an allowance. The gravel calculator builds compaction in.
Weight is a different question
Cubic yards say how much space, not how many tons. Weight depends on the material and its moisture, so for tons use the gravel or topsoil calculator, or ask your supplier for their density.
Uneven ground
Depth is an average. A low corner or a crown in the subgrade changes the volume faster than a small error in length or width.
Supplier increments
Delivery is often sold in set steps and may carry a minimum load. Ask your supplier before you round your own order.
This tool does not know what you are building. Slab thickness, base depth and fill specifications come from your local code, plans or contractor.
Common mistakes
Treating inches as feet
Multiplying 12 × 10 × 3 gives 360, not 30. Divide a depth in inches by 12 before multiplying, or use the depth field, which does it for you.
Confusing square yards with cubic yards
Square yards measure area (9 ft²). Cubic yards measure volume (27 ft³). A bulk order is almost always in cubic yards.
Ordering exactly what the math says
With a 0% allowance, any settling leaves you short. Decide your allowance before you place the order.
Questions people ask
How do you calculate 1 cubic yard?
One cubic yard is a cube 3 ft on each side: 3 × 3 × 3 = 27 cubic feet. To find how many yards you need, multiply length × width × depth in feet and divide by 27.
Why divide by 27 to get cubic yards?
There are 3 feet in a yard, and volume has three dimensions, so a cubic yard holds 3 × 3 × 3 = 27 cubic feet. The guide on how to calculate cubic yards has five worked examples.
How many yards of concrete do I need for a 20×20×4 slab?
20 × 20 × (4 ÷ 12) = 133.33 ft³, which is 4.94 yd³. With a 10% allowance it is 5.43 yd³. The concrete calculator also counts bags.
How many 2 cu ft bags are in a cubic yard?
27 ÷ 2 = 13.5, so 14 bags. For 3 ft³ bags it is 27 ÷ 3 = 9 bags.
How do I convert square feet to cubic yards?
Square feet alone cannot be converted. Multiply by the depth in feet first, then divide by 27. For 500 ft² at 3 in deep that is 4.63 yd³.
Related calculators and guides
Sources
Where the numbers come from
- NIST Handbook 44, Appendix C (cubic yard, cubic foot and meter definitions), accessed October 16, 2026.
- Texas A&M AgriLife Extension (Travis County) volume formula and bag-count example, accessed October 16, 2026.