Enter the FEV1 and FVC into the calculator to determine the FEV1/FVC ratio. This calculator can also evaluate any of the variables given the others are known.

Fev1/Fvc Ratio Formula

The following formula is used to calculate the FEV1/FVC ratio.

FEV1/FVC = (FEV1 / FVC) * 100


  • FEV1/FVC is the ratio of Forced Expiratory Volume in the first second to Forced Vital Capacity (%) FEV1 is the Forced Expiratory Volume in the first second (liters) FVC is the Forced Vital Capacity (liters)

To calculate the FEV1/FVC ratio, divide the FEV1 by the FVC, then multiply the result by 100 to get the percentage. This ratio is used to assess lung function and diagnose respiratory conditions like chronic obstructive pulmonary disease (COPD).

What is a Fev1/Fvc Ratio?

The FEV1/FVC ratio is a calculation used in the diagnosis of lung diseases, including chronic obstructive pulmonary disease (COPD) and asthma. It compares the amount of air a person can forcefully exhale in one second (FEV1) to the total amount of air a person can exhale (FVC). A lower than normal FEV1/FVC ratio suggests that the person has an obstructive lung disease.

How to Calculate Fev1/Fvc Ratio?

The following steps outline how to calculate the FEV1/FVC Ratio.

  1. First, determine the FEV1 value (liters).
  2. Next, determine the FVC value (liters).
  3. Next, use the formula FEV1/FVC = (FEV1 / FVC) * 100 to calculate the ratio.
  4. Finally, calculate the FEV1/FVC Ratio.
  5. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

FEV1 = 2.5 liters

FVC = 3.2 liters