Relative Humidity Calculator

Relative Humidity Formula:

\[ RH = \frac{\text{Actual Vapor}}{\text{Saturation Vapor}} \times 100 \]

Relative Humidity (RH):

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1. What is Relative Humidity?

Relative humidity (RH) is the ratio of the current amount of water vapor in the air to the maximum amount that the air could hold at that temperature, expressed as a percentage. It indicates how close the air is to being saturated with moisture.

2. How Does the Calculator Work?

The calculator uses the relative humidity formula:

\[ RH = \frac{\text{Actual Vapor}}{\text{Saturation Vapor}} \times 100 \]

Where:

\( Actual Vapor \) — Current vapor pressure in the air (hPa)
\( Saturation Vapor \) — Maximum vapor pressure the air can hold at that temperature (hPa)

Explanation: The formula calculates the percentage of moisture in the air relative to the maximum amount the air can hold at that specific temperature.

3. Importance of Relative Humidity Calculation

Details: Relative humidity is crucial for weather forecasting, climate studies, indoor comfort assessment, industrial processes, and agricultural applications. It affects human comfort, material preservation, and various biological processes.

4. Using the Calculator

Tips: Enter actual vapor pressure and saturation vapor pressure in hectopascals (hPa). Both values must be positive numbers. The calculator will compute the relative humidity percentage.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for relative humidity?
A: Relative humidity typically ranges from 0% (completely dry air) to 100% (saturated air, often resulting in fog or precipitation).

Q2: What is considered comfortable relative humidity for humans?
A: For most people, a relative humidity between 30% and 60% is considered comfortable. Below 30% can cause dry skin and respiratory irritation, while above 60% can feel muggy and promote mold growth.

Q3: How does temperature affect relative humidity?
A: Warmer air can hold more moisture, so relative humidity decreases as temperature increases (if moisture content remains constant), and increases as temperature decreases.

Q4: What instruments measure relative humidity?
A: Hygrometers and psychrometers are commonly used to measure relative humidity. Modern digital hygrometers provide direct readings, while psychrometers require calculations using dry-bulb and wet-bulb temperatures.

Q5: Why is relative humidity important in different industries?
A: Relative humidity is critical in HVAC systems, museums (for artifact preservation), pharmaceutical manufacturing, food processing, data centers, and agricultural operations where it affects product quality and process efficiency.