Mixing Ratio Calculator

The Mixing Ratio Calculator determines the mixing ratio and specific humidity from temperature and relative humidity. These parameters are essential for meteorological analysis, atmospheric science, and HVAC system design.

Modify the values and click the calculate button to use
Air Temperature °C
Relative Humidity %
Temperature Unit  
Atmospheric Pressure kPa
Output Units

Related Relative Humidity Calculator | Absolute Humidity Calculator | Psychrometric Calculator

Understanding Mixing Ratio and Specific Humidity

Mixing ratio and specific humidity are fundamental parameters in atmospheric science and HVAC engineering that describe the moisture content of air in different ways.

Key Definitions

Mixing Ratio (w)

Specific Humidity (q)

Calculation Methods

From Temperature and Relative Humidity

Step 1: Calculate saturated vapor pressure: es = 6.112 × exp[(17.67×T)/(T+243.5)]

Step 2: Calculate actual vapor pressure: e = (RH/100) × es

Step 3: Calculate mixing ratio: w = 0.622 × e / (P - e)

Step 4: Calculate specific humidity: q = w / (1 + w)

Where P is atmospheric pressure in kPa

Applications

Meteorology and Climate Science

HVAC and Building Systems

Industrial Applications

Typical Values

Environment Temperature RH Mixing Ratio
Arctic Winter -20°C 80% 0.8 g/kg
Temperate Climate 20°C 60% 8.7 g/kg
Tropical Climate 30°C 80% 21.6 g/kg
Desert Air 40°C 20% 9.4 g/kg

Advantages of Each Parameter

Mixing Ratio Advantages

Specific Humidity Advantages

Relationship to Other Parameters

Conversion Formulas

Mixing Ratio to Specific Humidity: q = w / (1 + w)

Specific Humidity to Mixing Ratio: w = q / (1 - q)

Mixing Ratio to Relative Humidity: RH = (w × P) / [0.622 × es(T)] × 100%

Mixing Ratio to Absolute Humidity: AH = w × ρd

Measurement and Instrumentation

Direct Measurement

Indirect Calculation

Accuracy Considerations

Error Sources

Best Practices

Practical Applications

Weather Forecasting

HVAC Design

Note: Mixing ratio and specific humidity calculations assume ideal gas behavior and standard atmospheric composition. For high-precision applications, consider corrections for real gas effects and atmospheric composition variations.