How to find a box's volume
A rectangular prism (a box) has volume V = length × width × height. Multiply the three dimensions together. A box measuring 4 × 5 × 6 holds 4 × 5 × 6 = 120 cubic units.
The formula is the base area multiplied by the height: 4 × 5 gives a 20-unit base, and stacking that base through 6 units of height gives 120. Every rectangular container follows this same base-times-height logic. The first factor is simply the footprint, which the rectangle area calculator gives you.
How to use this calculator
Enter the length, width, and height in the same unit. The result is in cubic units — cubic inches, cm³, m³, and so on. Order does not matter; multiplication is the same any way round.
Mixing units is the main pitfall: a length in metres with a width in centimetres produces a meaningless number. Remember too that cubic conversions are steep — 1 m³ equals 1,000,000 cm³, not 100. For shipping or storage, measure the internal dimensions if you want capacity, and the external ones if you need the space the box occupies.
Related solids
A pyramid with the same base and height holds one third of this box — see the pyramid volume calculator. For round containers, use the curved-surface ideas in the cylinder surface area calculator.
A cube is the special case where all three dimensions are equal, so its volume is simply the side cubed. Note that volume and surface area behave differently as a box grows: doubling every dimension multiplies surface area by four but volume by eight, which is why large containers are more material-efficient per unit of capacity.
Frequently asked questions
- What is the formula for a box's volume?
- V = length × width × height. Multiply all three dimensions together.
- What is the volume of a 4 × 5 × 6 box?
- 120 cubic units (4 × 5 × 6).
- What units is the volume in?
- Cubic units of whatever length unit you used — cubic inches, cm³, m³, litres, and so on.
- Does the order of the dimensions matter?
- No. Length × width × height gives the same result in any order.
- How do I convert the result to litres or gallons?
- If you measured in centimetres, divide the cubic-centimetre result by 1,000 to get litres — so a 4 × 5 × 6 cm box holds 0.12 litres. For US gallons from inches, divide the cubic-inch total by 231.