How to Calculate Cubic Feet (Formulas & Equations)
A cubic foot (ft³) is a unit of volume measuring one foot long by one foot wide by one foot deep. To calculate the volume of any rectangular 3-dimensional space:
Cubic Feet = Length (ft) × Width (ft) × Height (ft)
Example: 10 ft × 8 ft × 2 ft = 160 ft³.
Cubic Feet = (Length × Width × Height in inches) ÷ 1,728
Since 1 ft³ = 12 × 12 × 12 = 1,728 in³.
Cubic Feet to Cubic Yards (Cu Ft to Cu Yd) Conversion Table
In landscaping, concrete, and soil orders, materials are sold in cubic yards. Since 1 yard equals 3 feet, 1 cubic yard equals 3 × 3 × 3 = 27 cubic feet.
| Cubic Feet (ft³) | Cubic Yards (yd³) | Liquid Gallons (gal) | Cubic Meters (m³) |
|---|---|---|---|
| 27 ft³ | 1.00 cu yd | 202.0 gal | 0.765 m³ |
| 54 ft³ | 2.00 cu yd | 403.9 gal | 1.529 m³ |
| 81 ft³ | 3.00 cu yd | 605.9 gal | 2.294 m³ |
| 135 ft³ | 5.00 cu yd | 1,009.9 gal | 3.823 m³ |
| 270 ft³ | 10.00 cu yd | 2,019.7 gal | 7.646 m³ |
Frequently Asked Questions
How do I convert inches to cubic feet?▼
Multiply length, width, and height in inches, then divide the cubic-inch result by 1,728. For example, 24 × 18 × 12 inches equals 5,184 cubic inches, or 3 cubic feet.
How do I calculate concrete volume for a slab?▼
Convert slab thickness to feet, multiply length by width by thickness to obtain cubic feet, then divide by 27 for cubic yards. Add an appropriate waste allowance before ordering.
How many cubic feet are in a cubic yard?▼
There are exactly 27 cubic feet in one cubic yard because 3 ft × 3 ft × 3 ft equals 27 ft³.
How many cubic feet of mulch or soil do I need?▼
Multiply bed length in feet by width in feet and depth in feet. For depth measured in inches, divide the inches by 12 first. A 10 × 12 ft bed at 3 inches deep requires 30 cubic feet, or about 1.11 cubic yards.