Humidity Calculator
Calculate relative humidity or dew point from common weather readings
Calculation Steps
How Humidity Is Calculated
The calculator uses Magnus vapor pressure relationships to connect temperature, dew point, and relative humidity.
Relative humidity
Relative humidity compares actual water vapor to the maximum water vapor air can hold at the current temperature.
Dew point
Dew point is the temperature where air becomes saturated. A small air-dew point gap means condensation is easier to trigger.
Absolute humidity
Absolute humidity estimates grams of water vapor per cubic meter of air, which is useful when comparing different temperatures.
Humidity Examples
Common ways to connect temperature, dew point, and relative humidity.
Find relative humidity
70°F air with a 50°F dew point is about 49% relative humidity.
Find dew point
25°C air with 60% relative humidity gives a dew point near 17°C.
Condensation planning
A small air-dew point gap means windows, tools, or surfaces can reach condensation sooner.
Humidity Calculator FAQ
Common questions about relative humidity, dew point, absolute humidity, and condensation.
What does this humidity calculator solve?
It can calculate relative humidity from air temperature and dew point, or calculate dew point from air temperature and relative humidity.
Why does dew point matter for humidity?
Dew point is tied to the actual amount of water vapor in the air. Relative humidity changes when temperature changes, but dew point is often a clearer moisture signal.
What is a comfortable relative humidity range?
Many indoor comfort targets sit around 30% to 60% relative humidity. Comfort still depends on temperature, airflow, activity, and personal preference.
Can relative humidity be over 100%?
Supersaturation can occur in special atmospheric conditions, but ordinary planning calculations treat 100% as saturated air.
Is this a forecast or measurement tool?
No. It calculates humidity relationships from the values you enter. Use a calibrated sensor or local weather source for observed conditions.