Cubic Feet Calculator (ft³)
Calculate cubic feet from length, width, and height in inches or feet. Instant conversion to gallons, cubic yards, and storage capacity.
Multiplying length by width gives the footprint area; multiplying by height yields the full interior 3D volume.
Cubic feet equals Length × Width × Height (in feet). When measuring in inches, multiply Length × Width × Height and divide by 1,728 (since 12 × 12 × 12 = 1,728). For example, a 24×18×12 inch box has a volume of 5,184 ÷ 1,728 = 3.0 cubic feet (22.44 US gallons).
Cubic Feet Calculator (ft³) Formula & Sizing Rules
| Variable | Definition | Standard Units |
|---|---|---|
| ft³ | Cubic Feet of space | ft³ |
| L, W, H | Dimensions in inches or feet | in or ft |
| 1,728 | Number of cubic inches in one cubic foot (12³) | constant |
How to Calculate Cubic Feet from Any Measurement Unit
If all dimensions are measured in feet, multiply Length × Width × Height. If dimensions are in inches, multiply all three and divide by 1,728. If dimensions are in yards, multiply all three and multiply by 27. If in centimeters, multiply all three and divide by 28,316.85.
Common Project Sizing Mistakes
- Dividing cubic inches by 12 or 144 instead of 1,728 (12³ = 1,728)
- Confusing square feet (floor area) with cubic feet (3D volume)
Frequently Asked Questions
How do you calculate cubic feet?▼
How many gallons are in a cubic foot?▼
How many cubic feet are in a refrigerator or storage unit?▼
How do you convert cubic feet to cubic meters?▼
Authoritative Sources & Reference Standards
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811 — National Institute of Standards and Technology (NIST). Verified 2026-10-01.
Official SI unit definitions, conversion factors (Appendix B), and precision standards for cubic meters, liters, and US customary units.