Dew Point Calculator
Fill in the values and the answer updates as you type.
How the Dew Point Calculator works
Uses the Magnus formula with a = 17.625 and b = 243.04: γ = ln(RH ÷ 100) + a × T ÷ (b + T), and dew point = b × γ ÷ (a − γ), with T in °C. It is valid from about −45 °C to 60 °C. Comfort bands follow the dew point: up to 10 °C dry, up to 16 °C comfortable, up to 18 °C slightly humid, up to 21 °C humid, up to 24 °C very humid, above that oppressive. At 100% humidity the dew point equals the air temperature.
Inputs and results
The Dew Point Calculator takes 3 inputs and gives 3 results.
What you enter
- Air temperature — starts at 30.
- Relative humidity (%) — starts at 70.
- Temperature unit — starts at Celsius. Choose from: Celsius and Fahrenheit.
What you get
- Dew point (°C)
- Dew point (°F)
- How the air feels
Example: Dew Point Calculator with the starting values
With air temperature 30, relative humidity 70 % and temperature unit Celsius, the calculator returns:
| Dew point (°C) | 23.9 |
|---|---|
| Dew point (°F) | 75.1 |
| How the air feels | Very humid |
Change any value above and the results update straight away.
Dew Point Calculator FAQ
How do I use the Dew Point Calculator?
Enter air temperature, relative humidity and temperature unit in the fields, then read dew point (°c), dew point (°f) and how the air feels in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Dew Point Calculator calculate?
Dew point and how humid the air feels from temperature and relative humidity. It returns dew point (°c), dew point (°f) and how the air feels from the 3 values you provide.
What values does the Dew Point Calculator start with?
It opens with air temperature 30, relative humidity 70 % and temperature unit Celsius so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Dew Point Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Dew Point Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.