Relative Humidity Calculator

Enter air temperature and dew point in °C or °F to calculate relative humidity, vapor pressure, absolute humidity, wet bulb and humidity ratio locally.

Air temperature & dew point

Relative humidity changes with temperature even when the water-vapor content stays the same.

Air temperature

Dew point

Unit

If dew point exceeds air temperature, the entered state is supersaturated/inconsistent for this simple equilibrium model. The calculator caps displayed RH at 100%.

Psychrometric Calculator Dew Point Relative Humidity Absolute Humidity Wet Bulb

Relative humidity result

—Relative humidity

—Actual vapor pressure

—Saturation vapor pressure

—Temperature − dew point

—

Moisture-state cross-check

Add absolute humidity and an approximate wet-bulb estimate to the existing air-temperature/dew-point calculation.

Psychrometric evidence

Station pressure (hPa)

Metric	Value	Boundary / meaning

Moist-air pressure & drying-gap evidence

Use the air-temperature + dew-point state above to expose vapor pressure, saturation pressure, vapor-pressure deficit and condensation margin. This is a drying/condensation check, not a duplicate dew-point workflow.

Surface temperature for condensation checkSurface unit

—Relative humidity

—Vapor pressure

—Vapor-pressure deficit

—Surface vs dew point

Ready.

Evidence	Value	Interpretation	Use

Relative humidity is a ratio; vapor-pressure deficit expresses a different drying-pressure gap.

One moist-air state, several related properties

Relative humidity, dew point, wet bulb, vapor pressure, absolute humidity and humidity ratio describe different parts of the same moisture state. WebToolArc keeps the selected inputs visible and shows related outputs together instead of treating the terms as interchangeable.

Accuracy boundary

These browser calculations use standard psychrometric approximations. Real measurements can differ because of sensor calibration, station pressure, ventilation, radiation, local gradients and the exact saturation-vapor-pressure formulation. Use calibrated instruments and applicable engineering or meteorological standards when decisions require certified measurements.