Everyday / Browser calculator

Dew Point Calculator

Dew Point Calculator works from the inputs you provide and returns dew point (°c). Use the calculation panel to explore a scenario, then check the formula and limitations before applying the result.

Your inputs

Minimum: -45 · Maximum: 60
Minimum: 0.01 · Maximum: 100

Your results

Enter your values and calculate to see the result.

Formula and calculation method

γ = ln(RH/100) + 17.625T/(243.04+T). Dew point = 243.04γ/(17.625−γ).

Magnus approximation over liquid water. Ice conditions may need different coefficients.

How to use dew point calculator

  1. Set Temperature (°C). The example below uses 25.
  2. Set Relative humidity (%). The example below uses 60.
  3. Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.

Worked example

Example inputs
Temperature (°C)
25
Relative humidity (%)
60
Dew point (°C)
16.69766352

Factors affecting your result

Magnus approximation over liquid water. Ice conditions may need different coefficients.

Changing temperature (°c) changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.

Frequently asked questions

How does the dew point calculator work?

γ = ln(RH/100) + 17.625T/(243.04+T). Dew point = 243.04γ/(17.625−γ).

What inputs does Dew Point Calculator need?

Enter temperature (°c), relative humidity (%). Read the unit labels; percentages are entered as ordinary percentages, not decimal fractions.

How should I interpret the dew point calculator result?

Magnus approximation over liquid water. Ice conditions may need different coefficients.

Are my dew point calculator inputs uploaded?

No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.

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