Aquarium & reef calculators

Tank weight, heaters, volume, dosing and more. Every formula is tested against two published sources.

• Aquarium filter flow & turnover calculatorWhat filter flow (GPH) does your aquarium need? Enter tank size and type to get a target turnover, and check your filter against it.
• Aquarium heater size calculatorHow many watts does your aquarium heater need? Enter tank size and room temperature to get a wattage range and a heater to buy.
• Aquarium sand & substrate calculatorHow many pounds of sand, gravel or substrate does your tank need? Enter tank size and bed depth to get the weight to buy, with a diagram.
• Aquarium volume calculatorHow many gallons is your fish tank? Rectangle, cube, cylinder, bow-front, hexagon and corner tanks, plus the real water left after sand and headroom.
• Aquarium weight & stand load calculatorHow much does your filled fish tank weigh? Water, glass, substrate and rock, plus how much of your stand's rated capacity it uses.
• Salinity & specific gravity calculatorConvert hydrometer specific gravity to salinity in ppt, corrected for water temperature and calibration, and see how far you are from target.