Dew Point Calculator
How muggy the air feels.
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Weather
Relative Humidity Calculator
Enter temperature and dew point to get the relative humidity percentage.
Relative humidity
—
From temp & dew point.
| Comfort | — |
|---|---|
| Temperature | — |
| Dew point | — |
| — |
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Enter your figures above to see the step-by-step working.
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How the Relative Humidity Calculator Works
Relative humidity is the percentage of moisture the air holds compared with the most it could hold at that temperature. Given the air temperature and the dew point, you can work it back out exactly — when the two are equal the air is saturated at 100%, and the further apart they are, the drier the air.
This calculator uses the Magnus–Tetens saturation-vapour relationship to convert a temperature and dew point into relative humidity, and flags the comfort band.
RH = 100 × e^(γdew − γtemp)
Frequently Asked Questions
How do you find humidity from the dew point?
Relative humidity is the ratio of saturation vapour pressure at the dew point to that at the air temperature, times 100. This calculator does it with the Magnus formula.
What humidity is comfortable indoors?
Roughly 30–50% is the comfort sweet spot — low enough to avoid mugginess and mould, high enough to avoid dry skin.
What does 100% humidity mean?
The air is saturated: temperature equals dew point, and any further cooling produces dew, fog or rain.
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