Aquarium Volume Calculator
Calculate water volume, gross volume, surface area, and weight — with displacement and fill-gap options for realistic results.
- Liters & US gallons
- Surface area & weight estimate
- Substrate, rim gap & Hardscape offset
FAQ
How do I calculate the volume of my aquarium?
Measure the inside length, width, and height of your aquarium. This calculator uses those dimensions to calculate the tank volume and converts the result directly into liters and US gallons.
How many liters does my aquarium hold?
The exact water volume depends on the inner tank dimensions and how much space is taken up by substrate, rocks, wood, and equipment. The actual water volume is often lower than the theoretical gross volume.
Should I use inside or outside tank dimensions?
Always use inside glass dimensions. Measuring the outside of the tank ignores glass thickness and will overestimate the real water volume.
Does substrate and hardscape reduce aquarium water volume?
Yes. Substrate, rocks, driftwood, and internal equipment displace water. Depending on the layout, this can reduce usable water volume by 5–20%, which affects dosing, filtration, and stocking decisions.
Why is aquarium water volume important?
Water volume determines filter size, heater power, CO₂ dosage, fertilizer amounts, and safe fish stocking levels. Accurate volume calculation helps avoid instability and algae problems.
How do I convert liters to gallons for aquariums?
One liter equals 0.264 US gallons. This aquarium volume calculator automatically converts between liters and gallons for accurate equipment planning.
Does aquarium shape affect volume calculation?
Yes. Rectangular aquariums use length × width × height, while cylindrical tanks require diameter-based calculations. Using the wrong formula can significantly miscalculate volume.
How much does aquarium water weigh?
Freshwater weighs approximately 1 kg per liter (2.2 lb). Large aquariums can weigh several hundred kilograms, which is important for cabinet stability and floor load safety.