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

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?
Unit of temperature
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
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