Absolute Humidity Calculator
Calculate absolute humidity from relative humidity and temperature, or vice versa
Calculate Absolute Humidity
Air temperature for humidity calculation
Percentage of maximum moisture air can hold
Humidity Calculation Results
Absolute Humidity Conversions
Formula: AH = (RH × Ps) / (Rw × T × 100)
Where: Rw = 461.5 J/(kg⋅K)
Comfort Level: Slightly Humid
Note: Still comfortable for most people
Slightly Humid: Still comfortable for most people
Relative Humidity Comfort Guidelines
Example Calculation
Typical Summer Conditions
Air Temperature: 32°C (89.6°F)
Relative Humidity: 60%
Location: Warm, humid climate
Step-by-Step Solution
1. T = 32°C = 305.15 K
2. Ps = 4,755 Pa (saturation vapor pressure)
3. Pa = 0.6 × 4,755 = 2,853 Pa
4. AH = (60 × 4,755) / (461.5 × 305.15 × 100)
5. AH = 20.28 g/m³
Types of Humidity
Absolute Humidity
Mass of water vapor per unit volume (g/m³)
Relative Humidity
Percentage of maximum moisture capacity (%)
Specific Humidity
Mass of water vapor per unit mass of air
Mixing Ratio
Mass of water vapor per unit mass of dry air
Physical Constants
Applications
HVAC system design and control
Weather forecasting and meteorology
Agricultural and greenhouse management
Industrial process control
Building moisture management
Understanding Absolute Humidity and Atmospheric Physics
What is Absolute Humidity?
Absolute humidity is the actual amount of water vapor present in a given volume of air, expressed as mass per unit volume (g/m³ or kg/m³). Unlike relative humidity, it doesn't depend on temperature and provides a direct measure of atmospheric moisture content.
Key Differences
- •Absolute Humidity: Temperature-independent, actual moisture
- •Relative Humidity: Temperature-dependent, percentage of capacity
- •Units: AH in g/m³, RH in percentage
- •Applications: AH for processes, RH for comfort
Mathematical Formulation
AH = (RH × Ps) / (Rw × T × 100)
RH = (AH × Rw × T × 100) / Ps
Ps = Pc × exp[(Tc/T) × Σ(ai × τⁱ)]
- AH: Absolute humidity (kg/m³)
- RH: Relative humidity (%)
- Ps: Saturation vapor pressure (Pa)
- Rw: Water vapor gas constant (461.5 J/(kg⋅K))
- T: Temperature (K)
- τ: Reduced temperature (1 - T/Tc)
Note: The Wagner-Pruss equation provides high accuracy for saturation vapor pressure calculations.