Spirometry Interpreter Calculator

FEV1/FVC interpretation with severity classification.

Measured FEV1 (L)

Measured FVC (L)

Age (years)

Height (cm)

Sex (0=Male, 1=Female)

Tab to move between fields

FEV1/FVC Ratio

0.71

FEV1 % Predicted67.7%

FVC % Predicted74.8%

Predicted FEV1 (L)3.69

Predicted FVC (L)4.68

Pattern (0=Normal, 1=Obstr, 2=Restr, 3=Mixed)2

Severity (0=Normal to 5=Very Severe)2

Height M1.7

Lln Ratio0.7%

How to Use This Calculator

Enter measured FEV1 (L) and FVC (L) from your spirometry test report.
Enter age (years), height (cm), and sex to generate predicted normal reference values.
Review the FEV1/FVC ratio -- below 0.70 indicates airflow obstruction (COPD or asthma).
Check FEV1 and FVC as percent of predicted to classify severity (mild >=70%, moderate 50-69%, severe <50%).
Share results with your pulmonologist for interpretation in the context of symptoms and history.

How the result changes with Measured FVC (L)

Measured FEV1 (L): Forced expiratory volume in 1 second, measured in liters.
Measured FVC (L): Forced vital capacity, measured in liters.
Age (years): Patient age in years (18-95).
Height (cm): Patient height in centimeters.
Sex (0=Male, 1=Female): Biological sex for reference equation selection.

FEV1/FVC Ratio: Ratio of FEV1 to FVC. Below 0.70 suggests obstruction (GOLD criteria).
FEV1 % Predicted: Measured FEV1 as a percentage of age/sex/height-predicted value.
FVC % Predicted: Measured FVC as a percentage of predicted. Below 80% suggests restriction.
Predicted FEV1 (L): Reference FEV1 from Hankinson 1999 equations.
Predicted FVC (L): Reference FVC from Hankinson 1999 equations.
Pattern (0=Normal, 1=Obstr, 2=Restr, 3=Mixed): 0 = Normal, 1 = Obstructive, 2 = Restrictive (needs confirmation), 3 = Mixed.
Severity (0=Normal to 5=Very Severe): ATS/ERS severity: 0=Normal, 1=Mild, 2=Moderate, 3=Moderately Severe, 4=Severe, 5=Very Severe.

Identify Input Parameters
4 parameters
Measured FEV1 (L) = 2.5, Measured FVC (L) = 3.5, Age (years) = 45, Height (cm) = 170 = 5 input(s) provided
Calculate FEV1/FVC Ratio
FEV1/FVC Ratio = fev1 / fvc
0.714 = 0.714
Calculate FEV1 % Predicted
FEV1 % Predicted = (fev1 / predFev1) * 100
67.7 = 67.7
Calculate FVC % Predicted
FVC % Predicted = (fvc / predFvc) * 100
74.8 = 74.8