About TankCalc

TankCalc is a set of free calculators for freshwater and planted-tank hobbyists. It covers the math that comes up again and again: how many gallons a tank really holds, how big a water change you need, how much fertilizer to dose and whether the floor can take the weight.

Every calculator shows its formula and its assumptions, so you can check the result. Everything runs in your browser; nothing you type is sent anywhere.

Calculators are a starting point, not a substitute for testing your water and watching your fish. Spotted a mistake or have an idea? Suggestions are welcome.