Swimming Pool Heater BTU Calculator

Use the swimming pool heater calculator to determine the BTU size needed for your swimming pool. Enter all of your information using the drop down menus and click on the "calculate" button.

Heat rise varies when dealing with different swimming pool heaters. The usual recommendation is an increase of 1 to 1 and a half degree per hour. For further definitions, please scroll your mouse over the question marks.


  • Consult with a certified pool installer to verify the minimum heater size before placing an order OR contact our customer service team.
  • We recommend you size your heater one size larger than required


Most newer swimming pool heaters are 83% efficient. Pool heaters manufactured prior to 1996 are 78% efficient. Calculations are rough estimates as to which size pool heater you may need.

Please print out this page and consult with a certified pool installer.

Surface area of pool (Sq. ft):
Efficiency of heater (%):
Desired temperature rise (F):
Wind (mph):

Required Natural Gas Heater Output (BTU/Hr.):
Minimum Natural Gas Heater Size Required:
Required Propane Heater Output (BTU/Hr.):
Minimum Propane Heater Size Required:

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