Spirometry answers one question — is airflow obstructed? — while full lung volumes reveal restriction, air trapping, and hyperinflation. These calculators cover predicted FEV₁ and FVC, the obstruction ratio, TLC, RV, FRC, DLCO correction, and closing capacity. Use them to interpret PFT reports and understand the physiology behind the numbers.
13 calculators available
Primary spirometry ratio for detecting obstruction.
Expected forced vital capacity for age, height, and sex.
Reference FEV1 behind percent-predicted values.
Maximum air the lungs hold after a full breath in.
Air remaining after the most forceful exhale.
The lungs' resting volume between breaths.
Maximum inhale from a resting exhale.
Volume where small airways begin to collapse.
Size-independent measure of small-airway closure.
Diffusing capacity adjusted for hemoglobin.
Expected peak flow for home asthma monitoring.
Smoking-cessation counseling tool from FEV1.
Interactive map of all lung volumes and capacities.