Wet Bulb Temperature Calculator
Wet bulb from dry bulb and relative humidity.
Enter your values
Enter the dry bulb temperature in °F.
Enter the relative humidity in %.
Enter the cooler effectiveness in %.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Wet bulb temperature
- 74.1 °F
- In °C
- 23.4
- Wet bulb depression
- 20.9 °F
- Evaporative cooler outlet
- 77.2 °F
- Cooling potential
- 17.8 °F drop
Quick answer
Wet bulb temperature is the lowest temperature achievable by evaporation, setting the limit for evaporative cooling.
Stull approximation from dry bulb and RH
At a glance
| What it does | Wet bulb from dry bulb and relative humidity. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Dry bulb temperature, Relative humidity, Cooler effectiveness |
| Main output | Wet bulb temperature |
| Formula | Stull approximation from dry bulb and RH |
| Cost | Free — no sign-up, no download |
How to use the Wet Bulb Temperature Calculator
- 1Enter dry bulb temperature and relative humidity.
- 2Set the pad effectiveness — rigid media pads reach 80-90%.
- 3The outlet temperature shows what an evaporative cooler can actually deliver.
Inputs explained
- Dry bulb temperature(°F)
- Enter the dry bulb temperature in °F.
- Relative humidity(%)
- Enter the relative humidity in %.
- Cooler effectiveness(%)
- Enter the cooler effectiveness in %.
Worked example
Using the values the calculator loads with:
Inputs
- Dry bulb temperature95 °F
- Relative humidity35 %
- Cooler effectiveness85 %
Results
- Wet bulb temperature74.1 °F
- In °C23.4
- Wet bulb depression20.9 °F
- Evaporative cooler outlet77.2 °F
- Cooling potential17.8 °F drop
Frequently asked questions
Why does wet bulb matter?
It is the floor for evaporative cooling and sets cooling tower performance.
Dangerous wet bulb?
Sustained wet bulb above 88°F (31°C) makes heat stress dangerous even at rest.
What do I need to enter into the Wet Bulb Temperature Calculator?
Just 3 values: dry bulb temperature, relative humidity, cooler effectiveness. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Wet Bulb Temperature Calculator work out the answer?
Wet bulb temperature is the lowest temperature achievable by evaporation, setting the limit for evaporative cooling. It applies the formula Stull approximation from dry bulb and RH and shows the working so you can check each step by hand.
Is the Wet Bulb Temperature Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.