Free Tools
Interactive calculators built for freshwater aquariums and fishkeeping how-tos. No sign-up, no downloads — enter your numbers and get an answer you can act on.
Aquarium Volume Calculator
Turn tank dimensions into US gallons and liters, plus the filled water weight your stand and floor must hold.
Stocking Level Estimator
A starting-point estimate of how many fish fit your tank, by species adult size and the inch-per-gallon guideline.
Water Change & Dechlorinator Dose
How many gallons to swap at your chosen percentage, and how much dechlorinator to add for the new water.