Aquarium Calculators

What’s here

Six calculators we’ve built into our buying guides, gathered on one page. Each one works from your tank size and setup, and each sits inside the full guide for that equipment type if you want the reasoning behind the numbers.

Aquarium water volume calculator

Works out your actual water volume in litres from a tank’s dimensions, plus a sump’s volume if you have one. Every other calculator on this page depends on getting this number right first.

Aquarium heater wattage calculator

Enter your tank size for the heater wattage, or number of heaters, needed to hold temperature reliably.

Canister filter flow rate calculator

Enter your tank size for a target flow rate at 4 to 6 times turnover per hour, plus in-stock canister filters near that flow rate.

Pump flow rate calculator

Enter your tank size and setup type for a suggested circulation or wave-making flow rate.

Protein skimmer sizing calculator

Enter your total system volume and bioload for a skimmer rating, since the same skimmer suits a much smaller SPS tank than a fish-only one of the same size.

CO2 bubble rate starting-point calculator

Enter your tank size for a starting bubble rate. Treat the result as a starting point only: dial it in afterward using your drop checker’s colour, not the bubble count.

How these are built

Each calculator runs in your browser off the numbers you enter; nothing is sent to a server. The tank-size math behind them comes from published manufacturer ranges and standard turnover-rate conventions, referenced in full on each guide page.