Umidade saturação (aprox Tetens)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
This calculator estimates relative humidity using the Tetens approximation, a widely used method in climatology and engineering. The calculation is based on the ratio of actual vapor pressure (P) to saturation vapor pressure (Psat) at ambient temperature, multiplied by 100. The Tetens formula provides an approximate value for Psat, allowing for accurate relative humidity calculations under typical conditions.
The tool is particularly useful in construction projects, such as HVAC system sizing or assessing drying conditions for materials. To use it, simply enter the temperature and actual vapor pressure. The result shows the percentage of moisture in the air relative to its maximum capacity at that temperature.
Note that the Tetens approximation has limitations in extreme temperatures (below -30°C or above 50°C) and may not be suitable for high-precision scientific applications. Always check your project's specific requirements before applying the results.
Frequently asked questions
How does the Tetens formula compare to other relative humidity approximations?
The Tetens formula provides good accuracy for moderate temperatures and is simpler than methods like Magnus or Gilliland, but less precise than complex thermodynamic equations.
Can I use this calculator for weather forecasting?
Not recommended. This tool is designed for technical applications and cannot replace professional meteorological models that consider more environmental variables.
Why is relative humidity important in construction?
It affects the drying of materials like concrete and wood, thermal comfort in spaces, and the efficiency of designed climate control systems.
Are there temperature limitations for this calculation?
Yes. The formula may underestimate or overestimate values below -30°C or above 50°C, requiring more accurate methods in those cases.