How to Calculate Cubic Feet: Formula, Conversions & Free Tool
Cubic feet measure how much space something occupies in three dimensions. Whether you are sizing a shipping crate, estimating soil for a raised bed, or checking tank capacity, a free cubic feet calculator does the multiplication and unit conversion for you.
This guide covers the core formula, common conversions, and practical examples so you can trust the number before you buy materials or book freight.
Calculate volume in seconds
Convert L × W × H into cubic feet, yards, gallons, and liters — free in your browser.
The Cubic Feet Formula
For a rectangular box or room, volume is simply:
All three dimensions must use the same unit — ideally feet. A box that is 4 ft × 3 ft × 2 ft has a volume of 24 cubic feet.
Convert Other Units to Feet First
- Inches → feet: Divide by 12
- Yards → feet: Multiply by 3
- Meters → feet: Multiply by 3.28084
- Centimeters → feet: Divide by 30.48
Or skip the manual conversion: enter your units directly in the ToolMars cubic feet calculator.
Useful Volume Conversions
1 cubic yard = 27 cubic feet
1 cubic foot ≈ 7.48052 US gallons
1 cubic foot ≈ 28.3168 liters
1 cubic foot ≈ 0.028317 cubic meters
These conversions matter for landscaping (yards), aquariums and tanks (gallons/liters), and international shipping (cubic meters).
Real-world uses
- Estimating moving truck or storage unit capacity
- Ordering soil, mulch, or concrete by volume
- Checking whether a package fits a carrier's dimensional limits
Calculate volume in seconds
Convert L × W × H into cubic feet, yards, gallons, and liters — free in your browser.
Frequently Asked Questions
How do you calculate cubic feet?
Multiply length × width × height in feet. That product is your volume in ft³.
How many gallons are in a cubic foot?
About 7.48052 US gallons per cubic foot.
How many cubic feet are in a cubic yard?
Exactly 27. Divide ft³ by 27 to get cubic yards.
What is cubic feet used for?
Measuring 3D space for shipping, storage, landscaping materials, and liquid capacity.
Can I enter inches or meters into a cubic feet calculator?
Yes — choose your unit in the tool and it converts before calculating volume.