Enter the dry bulb temperature, wet bulb temperature, and relative humidity into the calculator to determine the Heat Stress Index.

Hsd Formula

The following formula is used to calculate the Hsd (Heat Stress Index) value.

Hsd = 0.5 * (T + W) + [(T - W) / (200 + 5 * H)]


  • Hsd is the Heat Stress Index T is the dry bulb temperature (°C) W is the wet bulb temperature (°C) H is the relative humidity (%)

To calculate the Heat Stress Index, add the dry bulb temperature and the wet bulb temperature, then multiply the result by 0.5. Subtract the wet bulb temperature from the dry bulb temperature, divide the result by the sum of 200 and the product of 5 and the relative humidity. Add the two results together to get the Heat Stress Index.