Heater wattage calculator
Aquarium Heater Wattage Calculator
Estimate heater size from tank volume and the temperature lift between your room and target aquarium temperature.
Tank volume unit
Common sizes
1 x 100 W
Recommended heater setup
Calculated load100 W
Rounded size100 W
Temperature lift8 F
Tank volume20 gal
Sizing note
For larger tanks, two smaller heaters are usually better than one oversized heater because heat spreads more evenly and one stuck heater is less likely to cook the tank.