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FEV1 / FVC Ratio Calculator

FEV₁ / FVC < 0.70 (or LLN) suggests airflow obstruction.

Compute the FEV₁/FVC ratio from spirometry. A post-bronchodilator ratio below 0.70 (or below the lower limit of normal) defines obstructive lung disease per GOLD criteria.

Priya Venkatesan By Priya Venkatesan
Published Last reviewed 1 min read

Inputs

L
L

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Ratio = FEV₁ / FVC

In depth

Compute the FEV₁/FVC ratio from spirometry. A post-bronchodilator ratio below 0.70 (or below the lower limit of normal) defines obstructive lung disease per GOLD criteria.