Lung Capacity Calculator

What is Lung Capacity?

Lung capacity refers to the total volume of air that your lungs can hold. It's an important measure of lung function and respiratory health. Lung capacity is composed of several different lung volumes, each representing a different aspect of breathing.

Lung Volumes and Capacities

• Tidal Volume (TV): The amount of air inhaled or exhaled during normal breathing.
• Inspiratory Reserve Volume (IRV): The additional air that can be inhaled after a normal inhalation.
• Expiratory Reserve Volume (ERV): The additional air that can be exhaled after a normal exhalation.
• Residual Volume (RV): The air remaining in the lungs after a maximal exhalation.
• Vital Capacity (VC): The total amount of air that can be exhaled after a maximal inhalation (TV + IRV + ERV).
• Total Lung Capacity (TLC): The total volume of air in the lungs after a maximal inhalation (VC + RV).

Formulas for Estimating Lung Capacity

The formulas used to estimate Vital Capacity (VC) are:

For males: \[VC = (27.63 - 0.112 \times age) \times \frac{height}{100}\]

For females: \[VC = (21.78 - 0.101 \times age) \times \frac{height}{100}\]

Where VC is in liters, age is in years, and height is in centimeters.

Calculation Steps

1. Input age, height, and gender.
2. Calculate Vital Capacity using the appropriate formula.
3. Estimate other lung volumes based on typical proportions:
   • Tidal Volume ≈ 12% of VC
   • Inspiratory Reserve Volume ≈ 60% of VC
   • Expiratory Reserve Volume ≈ 28% of VC
   • Residual Volume ≈ 30% of VC
4. Calculate Total Lung Capacity by adding Vital Capacity and Residual Volume.

Example Calculation

Let's calculate the lung volumes for a 30-year-old male who is 180 cm tall:

1. \[VC = (27.63 - 0.112 \times 30) \times \frac{180}{100} = 4.59 \text{ L}\]
2. Tidal Volume: \[TV = 4.59 \times 0.12 = 0.55 \text{ L}\]
3. Inspiratory Reserve Volume: \[IRV = 4.59 \times 0.6 = 2.75 \text{ L}\]
4. Expiratory Reserve Volume: \[ERV = 4.59 \times 0.28 = 1.29 \text{ L}\]
5. Residual Volume: \[RV = 4.59 \times 0.3 = 1.38 \text{ L}\]
6. Total Lung Capacity: \[TLC = 4.59 + 1.38 = 5.97 \text{ L}\]

Visual Representation

This diagram represents the different lung volumes for our example calculation. Green: Tidal Volume (TV), Blue: Inspiratory Reserve Volume (IRV), Yellow: Expiratory Reserve Volume (ERV), Red: Residual Volume (RV).