The conversion
cubic yards = cubic inches ÷ 46,656
cubic inches = cubic yards × 46,656
Where the number comes from: a yard is 36 inches, so a cubic yard is 36 × 36 × 36 = 46,656 cubic inches. Put another way, there are 1,728 cubic inches in a cubic foot and 27 cubic feet in a cubic yard: 1,728 × 27 = 46,656.
From inch measurements to cubic yards
When every dimension is in inches, you can skip converting to feet:
- Multiply length × width × depth in inches to get cubic inches.
- Divide by 46,656.
A form for a concrete pad, 48 × 48 × 4 in: 48 × 48 × 4 = 9,216 cubic inches. 9,216 ÷ 46,656 = 0.198 cubic yards, about 5.3 cubic feet.
A planter box, 72 × 24 × 18 in: 72 × 24 × 18 = 31,104 cubic inches = 0.667 cubic yards (18 cubic feet).
A 36-inch cube: 36 × 36 × 36 = 46,656 cubic inches = exactly 1 cubic yard.
When the area is in feet and the depth in inches
This is the most common mixed case, for example a 20 × 15 ft area 3 inches deep. You do not need cubic inches at all:
cubic yards = square feet × depth (in) ÷ 324
20 × 15 = 300 sq ft. 300 × 3 ÷ 324 = 2.78 cubic yards. The square feet to cubic yards converter does this, and the cubic yard calculator lets you mix inches and feet freely.
Cubic inches to cubic yards table
| Cubic inches | Cubic feet | Cubic yards |
|---|---|---|
| 1,000 | 0.579 | 0.0214 |
| 1,728 | 1 | 0.0370 |
| 5,000 | 2.89 | 0.107 |
| 10,000 | 5.79 | 0.214 |
| 23,328 | 13.5 | 0.5 |
| 25,000 | 14.47 | 0.536 |
| 46,656 | 27 | 1 |
| 50,000 | 28.94 | 1.07 |
| 100,000 | 57.87 | 2.14 |
| 250,000 | 144.68 | 5.36 |
| 500,000 | 289.35 | 10.72 |
| 1,000,000 | 578.70 | 21.43 |
Inch depths as fractions of a foot
If you prefer to work in feet, these are the depth conversions you will use most:
| Depth (in) | Feet | Cubic yards per 100 sq ft |
|---|---|---|
| 1 | 0.083 | 0.31 |
| 2 | 0.167 | 0.62 |
| 3 | 0.25 | 0.93 |
| 4 | 0.333 | 1.23 |
| 6 | 0.5 | 1.85 |
| 8 | 0.667 | 2.47 |
| 12 | 1 | 3.70 |
Common mistakes
- Dividing by 1,728 and stopping. That gives cubic feet, not cubic yards. Divide by 46,656, or divide the cubic feet by 27.
- Dividing by 36. A yard is 36 inches long, but a cubic yard is 36 inches in three directions, so the divisor is 36 × 36 × 36.
- Mixing feet and inches in one multiplication. 10 ft × 10 ft × 4 in is not 400 of anything useful. Convert everything to inches (120 × 120 × 4 = 57,600 cubic inches = 1.23 cubic yards) or everything to feet first.
Where cubic inches show up
Small containers and parts are often measured in cubic inches: shipping boxes, bins, molds, small concrete forms and engine displacement. To check a box against a cubic-foot rating, divide by 1,728; to compare it with a bulk delivery, divide by 46,656. The cubic feet calculator gives all three units at once.
Rounding early adds up. Keep the full cubic-inch figure until the last step, then round the cubic yards.
Questions people ask
- How many cubic inches are in a cubic yard?
- 46,656. A cubic yard is 36 in × 36 in × 36 in.
- How many cubic inches are in a cubic foot?
- 1,728 (12 × 12 × 12). There are 27 cubic feet in a cubic yard, and 27 × 1,728 = 46,656.
- How do I convert inches to cubic yards?
- If all three measurements are in inches, multiply them and divide by 46,656. If you have square feet and a depth in inches, multiply square feet by the inches and divide by 324.
- How many cubic yards is 100,000 cubic inches?
- 100,000 ÷ 46,656 = 2.14 cubic yards.