About the Volume Calculator
A volume calculator finds the space enclosed by a three-dimensional shape. Volume determines how much a container holds, how much material a pour requires, and how much air a room contains — the basis of shipping costs, concrete orders, and HVAC sizing.
The formula
V = length · width · heightFor a rectangular box, volume is simply the product of the three dimensions. All three must be in the same unit, and the result is in that unit cubed.
How to use this calculator
- 1Enter your Length. The field starts at
10, which you can overwrite. - 2Enter your Width. The field starts at
5, which you can overwrite. - 3Enter your Height. The field starts at
4, which you can overwrite. - 4Read the result straight away — it recalculates as you type, so there is no button to press. Use Share to copy a link that reopens the page with your exact numbers filled in.
Worked example
| Input | Value |
|---|---|
| Length | 10 |
| Width | 5 |
| Height | 4 |
Result
Box Volume: 200.00 cubic units
Those are the values the page loads with, so you can reproduce this result yourself and then change one field at a time to see what drives the outcome.
Understanding your result
Volume scales with the cube of linear size, which produces effects that consistently defy intuition. Doubling every dimension of a box multiplies its capacity by eight, not two. This is why shipping costs jump so sharply with parcel size, and why a slightly larger room needs disproportionately more heating.
Unit conversion is where volume calculations go wrong most often, because the conversion factor is cubed too. One foot is 12 inches, but one cubic foot is 1,728 cubic inches. One cubic metre is a thousand litres. Getting the linear conversion right and forgetting to cube it produces errors of orders of magnitude.
Things worth knowing
- Convert all dimensions to one unit before multiplying, not after.
- One cubic foot is 1,728 cubic inches; one cubic metre is 1,000 litres; one US gallon is 231 cubic inches.
- For cylinders use πr²h; for spheres, (4/3)πr³; for cones and pyramids, one third of the enclosing prism.
- Volumetric shipping weight is often based on dimensions rather than actual mass, since bulky light items occupy space.
- Break irregular shapes into simple solids, calculate each, and add.
Frequently asked questions
How do I calculate the volume of a box?+
Multiply length by width by height, with all three in the same unit. The answer is in that unit cubed — feet give cubic feet, centimetres give cubic centimetres.
How do I convert cubic feet to gallons?+
Multiply by 7.48 for US gallons, or 6.23 for imperial gallons. A 10 cubic foot tank holds about 74.8 US gallons.
How do I find the volume of a cylinder?+
Multiply the circular cross-section by the height: V = πr²h. A cylinder with radius 3 and height 10 holds π × 9 × 10 ≈ 282.7 cubic units.
Why does volume grow so fast with size?+
Because it depends on three dimensions at once. Doubling each dimension multiplies volume by 2³ = 8, which is why moderately larger containers hold dramatically more.