<-- Enter Temperature (T) in Fahrenheit
<-- Enter Relative Humidity (R) %
  

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How does the Heat Index Calculator work?
Free Heat Index Calculator - Given a temperature in Fahrenheit and a relative humidity percentage, this calculates the Heat Index.
This calculator has 2 inputs.

What 1 formula is used for the Heat Index Calculator?

HI = -42.379 + 2.04901523T + 10.14333127R - 0.22475541TR - 0.00683783T2 - 0.05481717R2 + 1.22874T2R + 0.00085282TR2 - 0.00000199T2R2

For more math formulas, check out our Formula Dossier
What 4 concepts are covered in the Heat Index Calculator?
fahrenheit
Unit of temperature
heat
energy that is transferred from one body to another as the result of a difference in temperature
heat index
measure of how hot it really feels when relative humidity is factored in with the actual air temperature
temperature
degree of hotness or coldness measured on a definite scale. An average measure of the kinetic energy for particles of matter.
Example calculations for the Heat Index Calculator