Aquarium heater wattage calculator
Calculate one Aqueon chart wattage from aquarium water volume and temperature rise.
Assumptions and limits
- The source chart uses a standard room temperature from 68°F through 72°F.
- The calculator supports 5 through 90 US gallons and a rise of more than 0°F through 15°F.
- The calculator uses water volume, not the aquarium label or outside dimensions.
- The result does not include tank shape, lid, drafts, exterior walls, water movement, placement, or equipment heat.
- A cold room, exterior wall, or outside door can require capacity beyond this chart.
This calculator is not professional certification, product approval, or a guarantee that an aquarium will hold its target temperature.
Choose a target temperature from reliable care requirements for the aquarium inhabitants. Tankstash does not choose that temperature.
Check the tank-size limits, placement rules, and operating instructions for the exact heater before use.
WARNING
WARNING: Follow the instructions for the exact heater. Electricity, water, hot surfaces, or a damaged heater can cause injury or property damage.
- Before you remove a heater, unplug it and let it cool for at least 30 minutes.
- After you put a heater in the aquarium, wait at least 30 minutes before you plug it in.
- Use a drip loop. Keep the cord and plug dry.
- Replace a heater that shows damage or wear.
- Use a separate aquarium thermometer. Monitor the water after installation and when room conditions change.
Method and sources
The Aqueon chart supplies all 21 wattage cells and its 68°F through 72°F room-temperature basis. Tankstash supplies only the upward band-selection rule.
Sources checked August 11, 2026.
This calculator does not use or extend the broader approximate table in the Tankstash Heater Size Guide.