Aquarium Calculators
Aquarium Volume Calculator (Litres & Gallons)
This aquarium volume calculator helps you estimate tank capacity from common aquarium dimensions so you can plan stocking, heating, filtration, dosing, and water changes more confidently.
Calculator
Try the Aquarium & Fish Tank Volume Calculator (Litres & Gallons)
Enter a few values to get a fast estimate. Results stay in your browser and can be copied, shared, or saved locally.
Units
Input preference
Rectangular tank volume
Estimated volume
0.0 US gal
Liters
0.0 L
Cubic volume
0 cubic units
Recent results
Saved history
Saved history stays on this device only and is not sent to our server.
No saved results yet.
Important note
These results are general aquarium planning estimates. They do not replace species-specific husbandry guidance, water testing, or experienced setup review.
Always verify stocking, heating, and equipment decisions against the needs of the fish, plants, and invertebrates you keep.
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Open calculatorFrequently asked questions
Does this show actual water volume after substrate and decor?
No. It is a geometric tank volume estimate, and actual filled water volume may be lower.
Can I use centimeters instead of inches?
Yes. The calculator accepts both inches and centimeters and returns gallons and liters.
Why is tank volume important?
Knowing tank volume helps with stocking plans, filter sizing, water changes, and additive dosing.
Does this work for irregular aquarium shapes?
It is mainly intended for simple rectangular tanks.
How this calculator works
- The calculator uses the values you enter and applies a simple formula directly in your browser.
- Results are produced client-side, so the page stays fast and the estimate updates without sending your form data to a server.
Input guide
- Choose inches or centimeters.
- Enter tank length, width, and height.
- Review the estimated volume in gallons and liters.
Result explanation
Aquarium planning often starts with tank dimensions, but many hobbyists still need a quick conversion to gallons and liters before they can make decisions.
This calculator focuses on simple rectangular tanks and is especially useful when comparing used tanks or checking setup ideas.
Helpful tips
- Recheck your inputs when the result looks higher or lower than expected.
- Save a few variations to history if you want to compare scenarios side by side.
- Use related calculators to cross-check feeding, sizing, travel, or aquarium decisions.
Common mistakes
- Mixing US and metric values in the same calculation.
- Using outdated food labels, product dimensions, or tank measurements.
- Treating an educational estimate as a substitute for veterinary, airline, or species-specific guidance.