# Calculator for Mixing Ratio of Water Vapor and Specific Humidity

Calculates the amount of water vapor in the air from barometric pressure, temperature and relative humidity. The mixing ratio indicates how many grams of water vapor are contained in one kilogram of dry air. The specific humidity, on the other hand, is the ratio of water vapor to moist air. Please enter the air pressure in hectopascals, the temperature in degrees Celsius and the relative humidity in percent to calculate the mixing ratio and specific humidity.

Example: at an air pressure of 1024 hPa, a temperature of 20 degrees centigrade and 50 percent humidity, the mixing ratio is 7.19 grams of water vapor per kilogram of dry air and the specific humidity is 7.14 grams of water vapor per kilogram of humid air.

The calculation is carried out using Peter Mander's approximation formulas: How to calculate Mixing Ratio and Specific Humidity

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