How to Calculate Cubic Yards (From Feet, Inches and Square Feet)
How to calculate cubic yards: multiply length × width × depth in feet and divide by 27. Includes square feet to cubic yards, inches to yards, tons to cubic yards, a conversion chart and worked examples.
Nestiex Team ·
The formula:
Cubic yards = length (ft) × width (ft) × depth (ft) ÷ 27
There are 27 cubic feet in a cubic yard, because 3 ft × 3 ft × 3 ft = 27. So you find the volume in cubic feet, then divide by 27.
The method is the same for gravel, soil, mulch, sand or concrete. This guide shows how to calculate cubic yards from feet, from inches and from square feet. It also shows how to convert tons to cubic yards for gravel. For gravel projects, the cubic yards gravel calculator does all of this instantly.
Step 1: Measure in feet
Measure the length and width of the area in feet. If a measurement is in inches, divide by 12. For example, 18 inches = 1.5 ft.
Step 2: Convert the depth to feet
Depth is usually measured in inches, so divide by 12:
| Depth (in) | Depth (ft) |
|---|---|
| 1 | 0.083 |
| 2 | 0.167 |
| 3 | 0.25 |
| 4 | 0.333 |
| 6 | 0.5 |
| 8 | 0.667 |
| 12 | 1.0 |
Step 3: Multiply and divide by 27
Example: an area 20 ft long, 10 ft wide and 4 inches deep.
- 4 in ÷ 12 = 0.333 ft
- 20 × 10 × 0.333 = 66.7 cubic feet
- 66.7 ÷ 27 = 2.47 cubic yards
Shortcut when depth is in inches
Cubic yards = length (ft) × width (ft) × depth (in) ÷ 324
Check: 20 × 10 × 4 ÷ 324 = 2.47 ✓
How to calculate cubic yards from square feet
If you already know the area in square feet:
Cubic yards = square feet × depth (in) ÷ 324
Example: 500 sq ft at 3 inches = 500 × 3 ÷ 324 = 4.63 cubic yards.
Square feet to cubic yards chart
| Area | 2 in deep | 3 in deep | 4 in deep | 6 in deep |
|---|---|---|---|---|
| 100 sq ft | 0.62 yd³ | 0.93 yd³ | 1.23 yd³ | 1.85 yd³ |
| 250 sq ft | 1.54 yd³ | 2.31 yd³ | 3.09 yd³ | 4.63 yd³ |
| 500 sq ft | 3.09 yd³ | 4.63 yd³ | 6.17 yd³ | 9.26 yd³ |
| 1,000 sq ft | 6.17 yd³ | 9.26 yd³ | 12.35 yd³ | 18.52 yd³ |
How to calculate cubic yards for other shapes
| Shape | Area formula | Then |
|---|---|---|
| Rectangle | length × width | × depth (ft) ÷ 27 |
| Circle | 3.1416 × radius² | × depth (ft) ÷ 27 |
| Triangle | ½ × base × height | × depth (ft) ÷ 27 |
| Trench | length × width | × depth (ft) ÷ 27 |
Circle example: a round bed 12 ft across (radius 6 ft), 3 inches deep.
- Area: 3.1416 × 36 = 113.1 sq ft
- Volume: 113.1 × 0.25 = 28.3 ft³
- Cubic yards: 28.3 ÷ 27 = 1.05 yd³
How to calculate tons to cubic yards (gravel)
Suppliers often sell gravel by the ton. Typical dry gravel weighs about 105 lb per cubic foot, or 2,835 lb (≈1.4 tons) per cubic yard (Engineering ToolBox). So:
- Cubic yards = tons ÷ 1.4
- Tons = cubic yards × 1.4
Example: 10 tons of gravel ÷ 1.4 = 7.1 cubic yards.
For other materials use their own density. Engineering ToolBox lists:
| Material | lb per cubic foot |
|---|---|
| Dry sand | 97 |
| Wet sand | 119 |
| Wet gravel | 125 |
More in how much a yard of gravel weighs and how much a ton of gravel covers.
Cubic feet to cubic yards
Divide cubic feet by 27.
| Cubic feet | Cubic yards |
|---|---|
| 27 | 1 |
| 50 | 1.85 |
| 100 | 3.70 |
| 250 | 9.26 |
| 500 | 18.52 |
Going the other way, multiply cubic yards by 27 to get cubic feet. Bagged material is usually sold by the cubic foot, so 1 cubic yard = 54 bags of 0.5 ft³. See how many bags of gravel you need.
Common mistakes
- Forgetting to convert inches to feet. 20 × 10 × 4 = 800 is not cubic feet. Divide by 12 first.
- Dividing by 9 instead of 27. 9 converts square feet to square yards, not cubic.
- Not allowing for compaction. Add 5–15% when ordering gravel or base material. Driveway guides commonly suggest 10–15% (HomeGuide).
Calculate cubic yards of gravel instantly
Enter length, width and depth in any units (ft, in, yd, m) into the cubic yards gravel calculator. It returns cubic yards, cubic feet, tons and bags. For a driveway with two layers, use the gravel driveway calculator.
Frequently asked questions
How do you calculate cubic yards? Length × width × depth, all in feet, then divide by 27.
How many square feet are in a cubic yard? It depends on depth: 1 cubic yard covers 324 sq ft at 1 inch, 162 sq ft at 2 inches, 108 sq ft at 3 inches and 81 sq ft at 4 inches.
How do I convert square feet to cubic yards? Square feet × depth in inches ÷ 324.
How many cubic feet are in a cubic yard? 27.
Sources
- Engineering ToolBox, Dirt and Mud – Densities: engineeringtoolbox.com
- HomeGuide, How Much Does a Gravel Driveway Cost? (2026): homeguide.com