Free Aquarium Tools
Practical, free online tools built for fishkeepers at every level. Size your tank accurately, convert units used in heater manuals and medication labels, and plan water changes down to the liter or gallon. Every tool runs in your browser — no account needed.
Available Tools
Aquarium Volume Calculator
Calculate how many liters or gallons your tank holds from internal length, width, and height. Supports centimeters and inches, and shows US and imperial gallon equivalents — ideal before buying a filter, dosing medication, or planning your first water change.
Use CalculatorAquarium Unit Converter
Instantly convert water temperature between Celsius and Fahrenheit, or volume between liters and US gallons. Essential when your heater dial, fish care guide, and medication bottle all use different units.
Use ConverterWater Change Calculator
Enter your aquarium volume and the percentage you plan to change to see exactly how much water to remove and replace. Use quick presets for 10%, 25%, or 50% changes and prepare the right amount before you start siphoning.
Use Calculator