Dew Point Calculator
Calculate dew point from temperature and relative humidity, calculate relative humidity from temperature and dew point, or calculate temperature from dew point and relative humidity with step-by-step solutions.
Input
Result
Visualization
Step-by-Step Solution
Calculate Dew Point
Select a calculation type and enter values to see results with detailed step-by-step solutions.
Complete User Guide
What is Dew Point?
Dew point is the temperature at which air becomes saturated with water vapor and condensation begins to form. It is a measure of atmospheric moisture. When the air temperature drops to the dew point, relative humidity reaches 100%, and water vapor condenses into liquid water (dew). The dew point is always less than or equal to the air temperature.
How to Use This Calculator
- Select a calculation type from the dropdown (Calculate Dew Point, Calculate Relative Humidity, Calculate Temperature, or Convert Units).
- Enter the required values in the input form.
- Select appropriate temperature units (Celsius, Fahrenheit, or Kelvin).
- Click 'Calculate' to see the results.
- Review the detailed results, visualizations, and step-by-step solution.
Calculation Types
Calculate Dew Point
Enter temperature and relative humidity to calculate dew point. Uses the Magnus formula for accurate calculations.
Calculate Relative Humidity
Enter temperature and dew point to calculate relative humidity. Formula: RH = 100 × exp((A×Td)/(B+Td) - (A×T)/(B+T)).
Calculate Temperature
Enter dew point and relative humidity to calculate temperature. Uses the Magnus formula rearranged.
Convert Units
Convert temperature values between Celsius, Fahrenheit, and Kelvin.
Magnus Formula
Dew Point Formula:
Td = (B × α) / (A - α)
Where:
- α = (A × T) / (B + T) + ln(RH/100)
- A = 17.27
- B = 237.7°C
- T = Temperature (°C)
- RH = Relative Humidity (%)
- Td = Dew Point (°C)
The Magnus formula is an empirical relationship that accurately calculates dew point from temperature and relative humidity. It is widely used in meteorology and HVAC applications.
Dew Point Comfort Levels
| Dew Point (°C) | Comfort Level | Description |
|---|---|---|
| < 10 | Dry | Very comfortable, dry air |
| 10 - 16 | Comfortable | Pleasant, comfortable conditions |
| 16 - 18 | Slightly Humid | Most people feel comfortable |
| 18 - 21 | Humid | Some discomfort, sticky feeling |
| 21 - 24 | Very Humid | Uncomfortable, oppressive |
| > 24 | Extremely Humid | Dangerous, heat exhaustion risk |
Important Notes
- Dew point cannot be greater than air temperature.
- Relative humidity must be between 0% and 100%.
- The calculator uses the Magnus formula, which is accurate for temperatures between -45°C and 60°C.
- Temperature conversions use standard formulas: F = C × 9/5 + 32, K = C + 273.15.
- Dew point is a better indicator of comfort than relative humidity alone.