Estimate the heater wattage needed to raise a tank's temperature.
Heater wattage scales with the water volume and how many degrees the tank must be warmed, giving a rough required wattage. An undersized heater can't hold temperature in winter, while oversized heaters risk rapid swings, so matching wattage to volume is important.
Aquarium Heater Watts
Watts ≈ gallons x temperature rise x 0.3
Watts ≈ gallons x temperature rise x 0.3 Heater wattage scales with the water volume and how many degrees the tank must be warmed, giving a rough required wattage.
An undersized heater can't hold temperature in winter, while oversized heaters risk rapid swings, so matching wattage to volume is important.
This calculator takes 2 inputs: Tank size, Temp rise needed. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.