Comprehensive Calculator Guide
The volume of a box or rectangular tank is length × width × height, and every 1,000 cm³ is one litre. A ground tank with inside dimensions of 3 × 2 × 2 m holds 12 m³, or 12,000 litres. Enter the dimensions in any unit to get the volume and the capacity in litres.
Tank capacity
Use inside dimensions, since walls take up space: a tank 3.4 × 2.4 × 2.2 m outside with 20 cm walls is about 3 × 2 × 2 m inside, nearly 6,000 litres less. Usable water is lower still, because the float valve stops filling below the top; use the water height if you want the real amount.
A litre of water weighs about a kilogram, so a full 12,000-litre tank holds roughly 12 tonnes, worth knowing before putting tanks or large pools on a roof.
Volumetric weight for shipping
Carriers charge light, bulky parcels by volumetric weight: volume in cm³ divided by a factor, often 5,000 for international express. A 60 × 40 × 40 cm box is 96,000 cm³, or 19.2 kg at 5,000, and you are usually billed for whichever of actual and volumetric weight is higher. Check your carrier's factor.
How to Use
- 01Enter length, width and height, choosing a unit for each.
- 02For tanks, use inside dimensions, or the water height for usable volume.
- 03Read the volume and the capacity in litres, and switch either result's unit if needed.
Formula Used
Volume = length × width × height | Litres = volume in cm³ ÷ 1,000Practical Examples
Example 1: ground water tank
3 × 2 × 2 m inside: 12 m³, or 12,000 litres.
Example 2: shipping box
60 × 40 × 40 cm: 96,000 cm³, 96 litres, 19.2 kg volumetric at a factor of 5,000.
Example 3: aquarium
100 × 40 × 50 cm: 200 litres, about 200 kg of water.
Important Tips
- Multiply cubic metres by 1,000 to get litres.
- For a tank split into chambers, calculate each and add them.
Common Mistakes to Avoid
- Using outside dimensions for a tank.
- Mixing metres and centimetres without converting.
Frequently Asked Questions
- How many litres are in a cubic metre?
- 1,000. A 5 m³ tank holds 5,000 litres.
- How do I convert cm³ to litres?
- Divide by 1,000: 96,000 cm³ is 96 litres.
- How do I work out volumetric weight?
- Divide the volume in cm³ by your carrier's factor, often 5,000.
- How much does the water in a tank weigh?
- About 1 kg per litre, so 12,000 litres is roughly 12 tonnes.