Aquarium Volume Calculator
Tank volume, stocking level and water changes.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Gross volume
- 78.5 US gallons
- Actual water volume
- 70.7 gallons (268 L)
- Weekly water change
- 17.7 gallons
- Filter turnover target
- 353 gph (5× per hour)
- Approximate filled weight
- 747 lb
Quick answer
Tank gallons equal length × width × height in inches divided by 231, minus roughly 10% for substrate and decor.
Gallons = L × W × H (in) ÷ 231
How to use the Aquarium Volume Calculator
- 1Measure the tank's inside dimensions in inches.
- 2Enter your weekly water change percentage.
- 3Read volume, turnover and weight.
Frequently asked questions
Why is actual volume lower?
Substrate, rock, decor and the gap below the rim typically take 10–15% of the nominal volume.
How strong should my filter be?
Aim for 4–6× tank volume per hour for community tanks, higher for messy or heavily stocked setups.