Relative Humidity Calculator

| Added in Physics

What is Relative Humidity?

Relative humidity is the ratio of the current amount of water vapor in the air to the maximum amount the air can hold at a given temperature. Understanding relative humidity is important for several reasons:

  1. Comfort: High relative humidity can make the air feel warmer, causing more sweating and discomfort. Low humidity makes air feel colder and can dry out skin and respiratory systems.

  2. Health: Proper humidity levels keep your skin, eyes, and respiratory tract in good condition.

  3. Home & Electronics: Excess humidity can cause mold and mildew, while very low humidity leads to static electricity that can damage electronics.

  4. Agriculture: Proper humidity levels are crucial for plant growth and storage of agricultural products.

How to Calculate Relative Humidity

The formula for relative humidity is:

[\text{Relative Humidity} = \left( \frac{\text{Actual Water Vapor Density}}{\text{Saturation Water Vapor Density}} \right) \times 100]

Where:

  • Actual Water Vapor Density is the amount of water vapor present in the air (g/m³)
  • Saturation Water Vapor Density is the maximum water vapor the air can hold at the current temperature (g/m³)

Steps to Calculate

  1. Measure the Actual Water Vapor Density using a hygrometer
  2. Determine the Saturation Water Vapor Density for the current temperature
  3. Divide actual by saturation and multiply by 100

Calculation Example

Given:

  • Actual Water Vapor Density: 10 g/m³
  • Saturation Water Vapor Density: 20 g/m³

[\text{Relative Humidity} = \left( \frac{10}{20} \right) \times 100 = 50%]

With an actual vapor density of 10 g/m³ and a saturation density of 20 g/m³, the relative humidity is 50%.

Ideal Humidity Levels

Environment Recommended RH
Indoor living spaces 30-50%
Storage areas 30-40%
Greenhouses 50-70%
Computer rooms 40-55%

Frequently Asked Questions

Relative humidity is the ratio of the current amount of water vapor in the air to the maximum amount the air can hold at a given temperature, expressed as a percentage.

Relative humidity is calculated by dividing the actual water vapor density by the saturation water vapor density, then multiplying by 100. The formula is: RH = (Actual Vapor Density / Saturation Vapor Density) × 100.

Relative humidity is affected by temperature, air pressure, and the presence of water vapor. As temperature increases, the air capacity to hold water vapor also increases, potentially lowering relative humidity if additional moisture is not added.

Most people find relative humidity between 30% and 50% comfortable. Below 30% can cause dry skin and respiratory issues, while above 60% can promote mold growth and feel uncomfortably muggy.