Patio base: 12 ft × 20 ft, 4 inches of gravel
12 × 20 = 240 square feet.
240 ft² × 4 in ÷ 324 = 2.96 yd³
Round up to the next amount your supplier sells, which here usually means 3 cubic yards.
Square Feet to Cubic Yards Converter
Multiply the square feet by the depth in inches, then divide by 324. At 3 inches deep, 100 square feet needs 0.93 cubic yards.
How the Square Feet to Cubic Yards Converter Works
Square feet measure the surface of a bed, lawn or slab. Cubic yards measure the material that fills it, so the depth of the layer is what turns one into the other.
Cubic yards = square feet × depth (in) ÷ 324
Cubic yards = square feet × depth (ft) ÷ 27
The 324, used across every CY Calculator tool, comes from two steps folded into one: 12 inches in a foot, and 27 cubic feet in a cubic yard. 12 × 27 = 324, so dividing by 324 converts the inches and the cubic feet at the same time.
- Find the area in square feet. For a rectangle, multiply the length by the width; for other shapes, the square feet calculator does it for you.
- Decide how deep the layer will be, in inches.
- Multiply the area by the depth and divide by 324.
Square Feet to Cubic Yards Chart
Cubic yards needed for common areas at the depths people use most.
| Area | 2 in deep | 3 in deep | 4 in deep | 6 in deep |
|---|---|---|---|---|
| 50 ft² | 0.31 yd³ | 0.46 yd³ | 0.62 yd³ | 0.93 yd³ |
| 100 ft² | 0.62 yd³ | 0.93 yd³ | 1.23 yd³ | 1.85 yd³ |
| 200 ft² | 1.23 yd³ | 1.85 yd³ | 2.47 yd³ | 3.7 yd³ |
| 250 ft² | 1.54 yd³ | 2.31 yd³ | 3.09 yd³ | 4.63 yd³ |
| 500 ft² | 3.09 yd³ | 4.63 yd³ | 6.17 yd³ | 9.26 yd³ |
| 750 ft² | 4.63 yd³ | 6.94 yd³ | 9.26 yd³ | 13.89 yd³ |
| 1,000 ft² | 6.17 yd³ | 9.26 yd³ | 12.35 yd³ | 18.52 yd³ |
| 2,000 ft² | 12.35 yd³ | 18.52 yd³ | 24.69 yd³ | 37.04 yd³ |
Typical Depths by Project
| Project | Typical depth |
|---|---|
| Fresh mulch on a garden bed | 2 to 3 in |
| Topsoil for a new lawn | 4 to 6 in |
| Gravel path or driveway topping | 2 to 4 in |
| Bedding sand under pavers | 1 in |
| Concrete patio slab | 4 in |
The guides on mulch, gravel and topsoil explain how to choose the depth for each job.
Square Feet to Cubic Yards Examples
Mulch for 850 square feet of beds, 3 inches deep
Add up the area of every bed first, then convert once.
850 ft² × 3 in ÷ 324 = 7.87 yd³
For the full method, including odd shaped areas, read how to convert square feet to cubic yards.
Square Feet to Cubic Yards FAQ
How many cubic yards do I need for 500 square feet?
It depends on the depth: 3.09 cubic yards at 2 inches, 4.63 at 3 inches, 6.17 at 4 inches and 9.26 at 6 inches.
Is there a shortcut for common depths?
Yes. At 3 inches deep, divide the square feet by 108. At 4 inches, divide by 81, and at 6 inches by 54. Each of those numbers is 324 divided by the depth.
How do I handle an area with an uneven depth?
Measure the depth at several evenly spaced points, add them up and divide by the number of readings. A bed that is 2 inches deep at one end and 4 inches at the other averages 3 inches, so convert at 3.
What if my depth is in feet?
Multiply the square feet by the depth in feet and divide by 27. A 400 square foot area dug 1.5 feet deep holds 400 × 1.5 ÷ 27 = 22.22 cubic yards.
More Converters
Need it the other way round? Use the cubic yards to square feet converter. To work out the volume of a whole bed, slab or trench first, the cubic yard calculator handles nine shapes and any mix of units.
- Cubic Yards to Tonsyd³ → tonsWeight of gravel, sand, soil, mulch or concrete from its volume.
- Tons to Cubic Yardstons → yd³How much space a weight of material fills, by material.
- Cubic Yards to Square Feetyd³ → ft²How many square feet a delivery covers at a chosen depth.
- Cubic Feet to Cubic Yardsft³ → yd³Divide by 27: bag sizes and small volumes in yards.
- Cubic Yards to Cubic Feetyd³ → ft³Multiply by 27: a delivery in cubic feet or bags.
- Cubic Yards to Cubic Metersyd³ → m³US yards to metric volume, with liters.
- Cubic Meters to Cubic Yardsm³ → yd³Metric volume to US yards, for quotes and plans.