Dew Point Calculator
The temperature at which air becomes saturated and dew forms.
Your numbers
°C
%
Your results
Dew point (°C)
Dew point (°C)
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Dew point (°F)
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Comfort
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Dew Point Calculator by TheCalcTools
How the Dew Point Calculator works
Enter the air temperature and relative humidity.
The Magnus formula relates saturation vapour pressure to temperature.
The dew point is the temperature at which the air would be 100% saturated.
The formula
γ = ln(RH ÷ 100) + 17.625 T ÷ (243.04 + T)Dew point = 243.04 γ ÷ (17.625 − γ)
Worked example
Using the default values shown in the calculator:
| Air temperature (°C) | 25 °C |
|---|---|
| Relative humidity | 60 % |
- At 25°C and 60% humidity, the dew point is 16.7°C (62.1°F).
- That feels: Humid.
Result:
| Dew point (°C) | 16.7 |
|---|---|
| Dew point (°F) | 62.1 |
| Comfort | Humid |
Frequently asked questions
Is dew point better than humidity for comfort?
Yes. Relative humidity depends on temperature, while dew point measures the absolute moisture in the air. Above about 20°C it feels muggy.
Why does fog form?
Fog forms when air cools to its dew point so water vapour condenses into droplets.
Sources and further reading
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.