Heat Stress Calculator

Calculate WBGT from environmental measurements, then assess heat stress using workload, acclimatization and clothing adjustment.

1. Environmental Conditions

Environment WBGT = 0.7(Tnwb) + 0.2(Tg) + 0.1(Tdb)

Temperature unit Use the same unit for all temperature inputs.

Natural wet bulb temperature (Tnwb)

°C

Natural wet bulb temperature measured without forced ventilation.

Globe temperature (Tg)

°C

Measures radiant heat using a globe thermometer.

Dry bulb temperature (Tdb)

°C

Air temperature measured with a shielded dry bulb thermometer.

2. Worker and Work Conditions

Workload Select the category that best represents the worker’s activity.

Acclimatization status Select unacclimatized for workers who are new or returning to hot work.

Clothing Adjustment values are entered internally in °C.

Body weight Obesity may increase susceptibility to heat strain.

Heat stress assessment —

Enter the required information and select Calculate.

Important: This calculator is a screening tool only. Use calibrated instruments and competent occupational health or industrial hygiene advice where required.