Box / room
Also: rectangular prism, bed, trench, room
V = L × W × H
L = length, W = width, H = height or depth.
Example: A box 12 × 10 × 8 in: 12 × 10 × 8 = 960 cu in = 0.56 cu ft = 15.7 liters.
Quick answer: cubic inches = length × width × height in inches. 1,728 cubic inches = 1 cubic foot; 231 cubic inches = 1 US gallon; 1 cubic inch = 16.387 cm³.
How to calculate cubic inches
- Measure each dimension in inches. Convert fractions to decimals, or type them directly, for example “10 1/2”.
- Multiply length × width × height for a box, or use the formula for your shape.
- Convert if needed: ÷ 1,728 for cubic feet, × 16.387 for cubic centimeters.
Cubic inches = L (in) × W (in) × H (in)
Cubic inch conversions
| Unit | Cubic inches |
|---|---|
| 1 cubic foot | 1,728 (exact) |
| 1 cubic yard | 46,656 (exact) |
| 1 US gallon | 231 (exact) |
| 1 UK gallon | 277.42 |
| 1 liter | 61.024 |
| 1 cubic centimeter | 0.061024 |
Cubic inches for other shapes
Cylinder
Also: round hole, post hole, tank, planter
V = π × r² × h
r = radius (half the diameter), h = height.
Example: A can 4 in across and 6 in tall: π × 2² × 6 = 75.4 cu in = 1.24 liters.
Sphere
Also: ball
V = 4⁄3 × π × r³
r = radius.
Example: A ball 6 in across: 4⁄3 × π × 3³ = 113.1 cu in.
Cone
Also: pile, mound, heap
V = 1⁄3 × π × r² × h
r = base radius, h = height.
Example: A cone 6 in across and 8 in tall: ⅓ × π × 3² × 8 = 75.4 cu in.
Hollow cylinder
Also: pipe, tube, ring, annulus
V = π × (R² − r²) × h
R = outer radius, r = inner radius, h = height.
Example: A tube 4 in outside and 3 in inside, 12 in long: π × (2² − 1.5²) × 12 = 66.0 cu in of material.
- Bigger volumes: use the cubic feet calculator or the cubic yards calculator. For liquids, see the tank volume calculator.
Frequently asked questions
How do I calculate cubic inches?
Multiply length × width × height, all in inches. A box 12 × 10 × 8 in is 960 cubic inches. For a cylinder, use π × radius² × height.
How many cubic inches are in a cubic foot?
1,728, because a cubic foot is 12 × 12 × 12 inches. Divide cubic inches by 1,728 to get cubic feet.
How many cubic inches are in a gallon?
A US gallon is exactly 231 cubic inches, and a UK (imperial) gallon is about 277.42 cubic inches.
How do I convert cubic inches to cubic centimeters or liters?
One cubic inch is exactly 16.387064 cubic centimeters (because 1 in = 2.54 cm exactly), and 1,000 cm³ is a liter. So 61.02 cubic inches make a liter.
How do I measure a box for shipping in cubic inches?
Measure the outside length, width and height in inches, rounding each up to the next whole inch as most carriers do, and multiply. Carriers then divide by their own “dim divisor” to get the dimensional weight; check your carrier’s current divisor.
What is engine displacement in cubic inches?
The volume swept by all the pistons: π × (bore ÷ 2)² × stroke × number of cylinders. Use the cylinder shape for one cylinder and set “How many?” to the cylinder count. A 350 cubic inch engine is about 5.7 liters.
Is this cubic inches calculator free to use online?
Yes. The CalcWall Cubic Inches Calculator is completely free and works online in any browser, on a phone, tablet or computer. There is nothing to download and no account to create, and the math runs right in your browser, so results appear as you type.