Tank & Container Litre Capacity Calculator
Estimate container capacity in litres for common shapes. Enter dimensions, choose your unit, and optionally set the fill percentage to calculate usable volume.
What a litre capacity calculator helps you do
A litre capacity calculator gives you a quick way to estimate how much a container can hold. Whether you are measuring a water tank, storage drum, planter box, aquarium, cooling loop reservoir, or a DIY mixing container, converting dimensions into litres makes planning far easier.
Instead of relying on rough guesses, you can calculate:
- Total capacity (maximum internal volume)
- Usable capacity at a chosen fill percentage
- Equivalent units like cubic meters and gallons
How to use this calculator
- Select the container shape (rectangular or cylinder).
- Pick your unit for all dimensions.
- Enter dimensions accurately from inner wall to inner wall.
- Set the fill percentage (100% for full volume, or less for usable volume).
- Click Calculate Capacity to see litres and converted values.
Formulas used
Rectangular container
Volume = Length × Width × Height
After volume is converted to cubic meters, litres are calculated as:
Litres = cubic meters × 1000
Cylindrical container
Volume = π × r² × h (where r is radius = diameter ÷ 2)
Then convert cubic meters to litres using the same multiplier:
Litres = cubic meters × 1000
Why fill percentage matters
Many real containers should not be filled to 100%. You might leave headspace for expansion, sloshing, aeration, or safety. This is common in fuel tanks, chemical storage, fermenting vessels, and transport containers.
Example: A tank with total capacity of 500 L at 80% fill gives a usable capacity of 400 L.
Quick conversion references
- 1 litre = 0.001 cubic meters
- 1 litre = 1000 cubic centimeters
- 1 litre ≈ 0.264172 US gallons
- 1 litre ≈ 0.219969 Imperial gallons
- 1 cubic foot ≈ 28.3168 litres
Common real-world uses
- Estimating rainwater harvesting tank size
- Sizing aquariums and fish tank filtration needs
- Calculating nutrient solution volume for hydroponics
- Determining liquid chemical batch volume
- Planning coolant, oil, or wash-water reservoir capacity
Common mistakes to avoid
- Using outside dimensions instead of internal dimensions
- Mixing units (for example, length in cm and height in inches)
- Ignoring curved corners, wall thickness, or fittings
- Assuming 100% fill is always safe or practical
FAQ
Can I use this for water, oil, or any liquid?
Yes. Capacity is geometric volume, so the formula works for any liquid. Weight and pressure change by liquid type, but litres do not.
Does this account for wall thickness?
No. Enter internal dimensions if you want accurate internal capacity.
Can I calculate partially filled tanks?
Yes. Use the fill percentage field to estimate usable litres at your chosen level.
What if my container is irregular?
Break it into simpler shapes and add their volumes, or use measured fill testing for best accuracy.