Physics

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Relative Humidity Calculator.

Calculate relative humidity from air temperature and dew point using the revised Magnus coefficients.

On-device calculationNo signup

Set your values

Results update as you type.

02 / ANSWER

Air temperature

Dew point

Relative humidity

0.000000%

Results update automatically as you type.

Educational model. Inputs and assumptions are explicit; verify engineering or scientific decisions independently.

Use Cases

Weather and Climate Monitoring

Helps meteorologists, hobbyists, and students quickly determine humidity levels from temperature and dew point data, useful for forecasting and understanding local climate conditions.

Example: Input a temperature of 25°C and a dew point of 15°C to find the relative humidity.

HVAC and Indoor Comfort

Assists in assessing indoor air conditions by calculating relative humidity from measured temperature and dew point, aiding in decisions about ventilation or humidification.

Example: Check if your living room's humidity is within the comfortable 30-50% range.

Frequently Asked Questions

How does the Relative Humidity Calculator work?: It uses the revised Magnus formula, which relates air temperature and dew point to relative humidity. You input both values, and the calculator applies the coefficients to compute the percentage of moisture in the air relative to saturation.
What are the revised Magnus coefficients?: They are empirical constants used in the Magnus formula to improve accuracy over a range of temperatures. The calculator uses these updated coefficients to provide more precise relative humidity estimates compared to older approximations.
Can I use this calculator for any temperature range?: The revised Magnus coefficients are designed for typical atmospheric conditions, generally from -40°C to 50°C. For extreme temperatures, results may be less accurate, but the calculator remains a reliable reference for most practical purposes.

Tips & Common Mistakes

Tips

Ensure both temperature and dew point are in the same unit (e.g., Celsius) for accurate results.
Use a reliable hygrometer or weather station to obtain accurate dew point readings.
Remember that relative humidity changes with temperature even if dew point stays constant.
For quick estimates, you can use the calculator to compare different scenarios, like how humidity varies with temperature changes.

Common Mistakes to Avoid

Mixing units, such as entering temperature in Fahrenheit and dew point in Celsius, which leads to incorrect results.
Assuming that relative humidity is a fixed value; it varies with temperature, so always input current conditions.
Using the calculator for extreme temperatures outside the intended range without considering potential inaccuracies.

Last updated: August 13, 2026

Use Cases

Weather and Climate Monitoring

Helps meteorologists, hobbyists, and students quickly determine humidity levels from temperature and dew point data, useful for forecasting and understanding local climate conditions.

Example: Input a temperature of 25°C and a dew point of 15°C to find the relative humidity.

HVAC and Indoor Comfort

Assists in assessing indoor air conditions by calculating relative humidity from measured temperature and dew point, aiding in decisions about ventilation or humidification.

Example: Check if your living room's humidity is within the comfortable 30-50% range.

Frequently Asked Questions

How does the Relative Humidity Calculator work?

It uses the revised Magnus formula, which relates air temperature and dew point to relative humidity. You input both values, and the calculator applies the coefficients to compute the percentage of moisture in the air relative to saturation.

What are the revised Magnus coefficients?

They are empirical constants used in the Magnus formula to improve accuracy over a range of temperatures. The calculator uses these updated coefficients to provide more precise relative humidity estimates compared to older approximations.

Can I use this calculator for any temperature range?

The revised Magnus coefficients are designed for typical atmospheric conditions, generally from -40°C to 50°C. For extreme temperatures, results may be less accurate, but the calculator remains a reliable reference for most practical purposes.

Tips & Common Mistakes

Tips

Ensure both temperature and dew point are in the same unit (e.g., Celsius) for accurate results.
Use a reliable hygrometer or weather station to obtain accurate dew point readings.
Remember that relative humidity changes with temperature even if dew point stays constant.
For quick estimates, you can use the calculator to compare different scenarios, like how humidity varies with temperature changes.

Common Mistakes to Avoid

Mixing units, such as entering temperature in Fahrenheit and dew point in Celsius, which leads to incorrect results.
Assuming that relative humidity is a fixed value; it varies with temperature, so always input current conditions.
Using the calculator for extreme temperatures outside the intended range without considering potential inaccuracies.

Use Cases

Weather and Climate Monitoring

Helps meteorologists, hobbyists, and students quickly determine humidity levels from temperature and dew point data, useful for forecasting and understanding local climate conditions.

Example: Input a temperature of 25°C and a dew point of 15°C to find the relative humidity.

HVAC and Indoor Comfort

Assists in assessing indoor air conditions by calculating relative humidity from measured temperature and dew point, aiding in decisions about ventilation or humidification.

Example: Check if your living room's humidity is within the comfortable 30-50% range.

Frequently Asked Questions

How does the Relative Humidity Calculator work?

What are the revised Magnus coefficients?

Can I use this calculator for any temperature range?

Tips & Common Mistakes

Tips

Ensure both temperature and dew point are in the same unit (e.g., Celsius) for accurate results.
Use a reliable hygrometer or weather station to obtain accurate dew point readings.
Remember that relative humidity changes with temperature even if dew point stays constant.
For quick estimates, you can use the calculator to compare different scenarios, like how humidity varies with temperature changes.

Common Mistakes to Avoid

Mixing units, such as entering temperature in Fahrenheit and dew point in Celsius, which leads to incorrect results.
Assuming that relative humidity is a fixed value; it varies with temperature, so always input current conditions.
Using the calculator for extreme temperatures outside the intended range without considering potential inaccuracies.