Fish Tank Heater Calculator
Size heater wattage for aquariums
gal
°F
Formula
Watts = Gallons × Temp Diff × 0.5
Rule of thumb: 0.5 watts per gallon per degree of heating needed.
Examples
20 gal, 10°F difference
100W heater recommended.
Frequently Asked Questions
About Fish Tank Heater
Size aquarium heater wattage based on tank volume and temperature needs.