Aquarium tools
Small, honest calculators for everyday tank maths — each one feeds straight into the stocking planner.
7 tools, free and without an account. None of them guesses: each shows the numbers behind its answer and says plainly where the estimate stops and a measurement has to start.
Tank and equipment
The physical box and what you hang on it — capacity, heat and light.
- Aquarium volume calculatorLitres and US gallons from tank dimensions — then see what actually fits in it.
- Aquarium heater size calculatorA wattage guideline from tank volume and how far above room temperature you're heating.
- Aquarium lighting calculatorHow much light actually reaches your substrate, how long to run it, and whether it suits the plants you have.
Water and chemistry
What comes out of your tap, what you change, and what you add.
- Tap water match: which fish suit your water?Enter your tap's pH and hardness — see which of our 222 species would thrive in it untreated.
- Water change calculatorHow many litres to drain — and what the change actually does to dissolved waste.
- Dosing calculatorScale any bottle's dose rate to your exact water volume.
Reference
Quick conversions for when a guide is written in someone else's units.