Quick answer: cubic feet = length × width × height, all in feet. Working in inches? Multiply the three and divide by 1,728 — because a cubic foot is 12 × 12 × 12 inches. From centimetres, divide by 28,317.
Conversion factors worth knowing
| To convert | Do this | Example |
|---|---|---|
| Cubic inches → ft³ | ÷ 1,728 | 5,184 in³ = 3 ft³ |
| Cubic cm → ft³ | ÷ 28,317 | 56,634 cm³ = 2 ft³ |
| Cubic metres → ft³ | × 35.315 | 2 m³ = 70.6 ft³ |
| Cubic yards → ft³ | × 27 | 3 yd³ = 81 ft³ |
| ft³ → cubic metres (CBM) | × 0.02832 | 500 ft³ = 14.16 m³ |
| ft³ → US gallons | × 7.4805 | 10 ft³ = 74.8 gal |
| ft³ → litres | × 28.317 | 10 ft³ = 283 L |
Cubic feet in the real world
| Item | Cubic feet |
|---|---|
| Small moving box (16 × 12 × 12 in) | 1.33 |
| Medium moving box (18 × 18 × 16 in) | 3.0 |
| Large moving box (18 × 18 × 24 in) | 4.5 |
| Standard refrigerator | 18–25 |
| Chest freezer (medium) | 7–10 |
| Washing machine drum | 3.5–5.5 |
| Full-size pickup bed | 50–65 |
| 5 × 5 ft storage unit (8 ft ceiling) | 200 |
| 10 × 10 ft storage unit | 800 |
| 10 × 20 ft storage unit | 1,600 |
| 20 ft shipping container | ≈ 1,170 |
| 40 ft shipping container | ≈ 2,390 |
For moving estimates, a widely used rule of thumb is 150 to 200 cubic feet per furnished room. A one-bedroom apartment lands around 300–400 ft³, a two-bedroom 600–800, and a three-bedroom house 1,200–1,600. Movers quote by volume because a truck almost always fills up before it hits its weight limit.
Common mistakes & pro tips
- Dividing inches by 12 once instead of three times. All three dimensions must convert. That is why the shortcut divisor is 1,728, not 12.
- Outside dimensions for capacity. A box's usable volume is measured inside the walls — significant on thick-walled containers and coolers.
- Assuming 100% packing efficiency. Real loads pack at 80–85% because of irregular shapes and voids. Add headroom to any moving estimate.
- Confusing ft³ with square feet. Storage units are advertised by floor area; the usable volume depends on ceiling height too.
- Pro tip — for freight, calculate CBM. International shipping quotes in cubic metres. Multiply ft³ by 0.02832, or use the freight volume calculator.
- Pro tip — the 12-inch cube. Picture a 12-inch cube: that is exactly one cubic foot, and it makes estimating a room by eye much easier.
Frequently asked questions
How do I calculate cubic feet?
Multiply length × width × height with all three in feet. If your measurements are in inches, either divide each by 12 first or multiply them together and divide the result by 1,728. A box 24 × 18 × 12 inches is 5,184 in³ ÷ 1,728 = 3 cubic feet.
How many cubic inches are in a cubic foot?
1,728, because a cubic foot is 12 × 12 × 12 inches. This is the single most useful conversion factor for anyone working with boxes and small containers, and it is why a 12-inch cube is exactly one cubic foot.
How do I convert cubic feet to cubic meters?
Multiply cubic feet by 0.0283, or divide by 35.31. International freight is quoted in cubic metres, so a 500 ft³ shipment is 500 ÷ 35.31 ≈ 14.16 CBM. Going the other way, multiply cubic metres by 35.31.
How many cubic feet is my refrigerator?
Measure the interior width, depth and height in inches, multiply them, and divide by 1,728. A compartment 28 × 26 × 40 inches gives 29,120 ÷ 1,728 ≈ 16.9 cubic feet. Manufacturers quote total capacity across all compartments, so measure the fridge and freezer sections separately and add them.
How many cubic feet do I need for moving?
A rough planning figure is 150 to 200 cubic feet per fully furnished room. A one-bedroom apartment typically runs 300 to 400 cubic feet, a three-bedroom house 1,200 to 1,600. Movers quote in cubic feet precisely because volume, not weight, usually fills the truck first.