Aquarium Volume Calculator
Find an aquarium’s water volume in liters and gallons from its dimensions, with an allowance for substrate and freeboard. Calculates in your browser.
Water volume
-
Show the math
Volume is the tank's internal dimensions multiplied together, then converted to liters and gallons:
liters = length × width × height (cm) ÷ 1000
A cylinder uses π × r² × height. The "filled to" percentage accounts for substrate, rocks and the gap left below the rim, so set it to match your tank: the real water volume is always less than the gross capacity.
1 US gallon = 3.785 L · 1 imperial gallon = 4.546 L. Everything is calculated in your browser.
What this does
An aquarium volume calculator finds a tank’s water volume in liters and gallons from its dimensions, with an allowance for substrate and freeboard.
How to use it
- Choose the tank shape.
- Enter the dimensions.
- Set the "filled to" percentage.
- Read liters and gallons.
How it works
Cylinders use π × r² × height. Substrate, rocks, and the gap below the rim mean the real water volume is less than the gross size; the "filled to" percentage allows for that.
liters = L × W × H (cm) ÷ 1000
Understanding your result
The real water volume is less than the gross size once substrate, rocks, and the gap below the rim are counted, so set the "filled to" percentage to match your tank and use the adjusted figure when dosing treatments or choosing stock levels. Overstocking and overdosing both trace back to an overestimated volume.
Example
A 60 × 30 × 36 cm tank is 64.8 liters gross; filled to 90% it holds about 58.3 liters (15.4 US gallons).
Last updated .
Frequently asked questions
How do I work out tank volume?
Multiply length × width × height (in cm) and divide by 1000 for liters; cylinders use π × r² × height. The tool also converts to US and imperial gallons.
Why is actual water less than the size?
Substrate, rocks and the gap below the rim take up room, so the real water volume is less than the gross capacity. Set the "filled to" percentage to match your tank.
Is anything stored?
No. Everything is calculated locally in your browser.
Related tools
Dog Age Calculator
Convert your dog’s age to human years using the size-based chart method, with the 2020 epigenetic clock for reference. Calculates in your browser.
Cat Age Calculator
Convert your cat’s age to human years with the standard feline chart and see its life stage. Calculates in your browser.
Puppy Weight Calculator
Estimate a puppy’s adult weight from its current weight and age using the linear growth-rate method. Calculates in your browser.
Pet Food Portion Calculator
Turn a daily calorie target into cups and grams of food per day and per meal, using the energy figures on the bag. Calculates in your browser.