Dew Point Calculator
Magnus approximation: γ = ln(RH/100) + 17.625T/(243.04+T); dew point = 243.04γ/(17.625−γ).
Inputs and units
- Air temperature: Enter your value in the format and unit shown.
- Temperature unit: Choose Celsius, Fahrenheit.
- Relative humidity (%): Enter your value in the format and unit shown.
Calculation method
Magnus approximation: γ = ln(RH/100) + 17.625T/(243.04+T); dew point = 243.04γ/(17.625−γ).
Worked example
The example values are: Air temperature = 25; Temperature unit = C; Relative humidity (%) = 60
- Dew point (°C): 16.6976635212
- Dew point (°F): 62.0557943382
Assumptions and limitations
Approximation over liquid water; frost point differs below freezing.
Using your result
Select Calculate after changing inputs. Copy result copies the displayed output; Download result saves a text file. Reset returns the form to its example inputs. Calculations run in your browser.
Dew Point Calculator FAQs
What method does this calculator use?
Magnus approximation: γ = ln(RH/100) + 17.625T/(243.04+T); dew point = 243.04γ/(17.625−γ).
What should I check before using the result?
Approximation over liquid water; frost point differs below freezing.