Aquarium calculators
Quick, accurate answers for setting up and maintaining a fish tank. Each calculator shows its formula.
Looking for how many fish you can keep? That's the stocking calculator. It checks bioload, water and compatibility together.
Aquarium volume calculator
Work out how many gallons or litres your tank holds, for rectangular, cylinder, bow front, corner and hexagon tanks.
Aquarium weight calculator
Estimate the full weight of your aquarium with water, glass, substrate and rock, so you can check your stand and floor.
Aquarium gravel and sand calculator
Find how many pounds or kilograms of gravel, sand or aquasoil you need for the depth you want.
Aquarium heater size calculator
Find the right heater wattage for your tank size, room temperature and target water temperature.
Aquarium filter flow rate calculator
See what filter flow rate (GPH or L/h) your tank needs, and check whether your current filter is enough.
Water change and nitrate calculator
See how much a water change lowers nitrate, and how many changes it takes to reach a target.
Aquarium CO2 calculator (pH and KH)
Estimate dissolved CO2 in a planted tank from your pH and KH readings.
Aquarium unit converter
Convert gallons and litres, Fahrenheit and Celsius, inches and centimetres, and dGH, dKH and ppm.