Fish Tank Volume Calculator
Knowing your aquarium's actual volume in litres is essential for sizing a filter or heater correctly, dosing water treatments accurately, and working out safe stocking levels. Use the calculator below in centimetres or feet — whichever you measured in.
Fish Tank Volume Calculator
Work out your aquarium's volume in litres to correctly size a filter, heater, or stocking level.
Frequently Asked Questions
Why is my actual water volume less than the calculated figure?
The calculator gives the tank's total internal volume. Substrate, rocks, decor, and equipment like filters and heaters all displace water, so the real water volume is typically 5-15% less depending on how heavily the tank is decorated.
Does tank shape affect the calculation?
This calculator assumes a standard rectangular or cube tank. Bow-front, hexagonal, and other non-rectangular tanks will hold a different volume than a straightforward length × width × height calculation suggests.