FEV1/FVC Ratio Calculator (Tiffeneau Index)

Your details

Direct mode: enter your measured values and get the ratio and pattern. Predicted mode: also enter age, sex, height, and ethnicity to see percent-predicted values.
Forced Expiratory Volume in 1 second: the volume of air forcefully exhaled in the first second of a maximal exhalation. Enter the best value from at least three acceptable efforts.
L
Forced Vital Capacity: the total volume of air exhaled with maximum effort from full inspiration. FVC should be the largest value from three or more acceptable maneuvers.
L
FEV1/FVC ratioNormal
78%

Tiffeneau-Pinelli index: the fraction of FVC exhaled in the first second

Ventilatory patternNormal - no obstruction detected
78% ratio
Severely obstructed<50%Obstructed50%-65%Borderline65%-70%Normal-low70%-80%Normal80%+

FEV1/FVC ratio: 78.0% - Normal - no obstruction detected.

  • A ratio at or above the threshold indicates no airflow obstruction on today's test.
  • Normal spirometry does not rule out all lung disease; conditions such as early emphysema, mild asthma, or respiratory muscle weakness can be present with a normal ratio.
  • These results are for informational purposes only. A qualified clinician should interpret spirometry in the context of your clinical history, symptoms, and examination findings.

Next stepIf symptoms persist despite a normal result, ask your clinician about full pulmonary function tests, including lung volumes and diffusing capacity (DLCO).

 = Powered by OnlyCalculators