Aquarium Heater Size
Recommended heater wattage for your tank.
How to Use the Aquarium Heater Size
Enter tank size in gallons and the temperature rise needed (difference between room temperature and target tank temperature). The calculator recommends heater wattage.
Common Uses
- Selecting the right heater before purchase
- Planning for cold-room installations
- Heating tropical fish tanks accurately
Frequently Asked Questions
What wattage heater do I need?
A common rule is 3–5 watts per gallon. Use higher wattage if the room is cold or the temperature difference is large.
Should I use one large or two smaller heaters?
For tanks over 40 gallons, two heaters (one each end) provide more even heating and redundancy.
Is this tool free?
Yes, completely free.