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FEV1 FVC Ratio Calculator

Work out fev1 fvc ratio instantly with clear inputs, formula shown and shareable results.

About FEV1 FVC Ratio Calculator

Divides FEV1 by FVC, the ratio that separates obstructive from non-obstructive spirometry patterns.

Formula

FEV1/FVC

Ratio (%) = FEV1 / FVC x 100; the fixed GOLD cut-off for obstruction is 70%

Worked example

With the default values below, FEV1 FVC Ratio Calculator returns FEV1/FVC ratio of 76.2%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Measured FEV1accepts 0.2–7 L
3.2 L
Measured FVCaccepts 0.3–9 L
4.2 L

Results

FEV1/FVC ratio
76.2%
Ratio as a decimal
0.762
Pattern
No obstruction by the fixed 0.70 ratio

Step by step

  1. 1Values used
  2. 2FEV1/FVC
  3. 3FEV1/FVC ratio= 76.2
  4. 4Ratio as a decimal= 0.762
  5. 5Pattern= No obstruction by the fixed 0.70 ratio

Assumptions and limits

  • The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

Fixed ratio or lower limit of normal?

GOLD uses a fixed 0.70 post-bronchodilator ratio; the lower limit of normal avoids over-diagnosis in older people.

Does a normal ratio exclude disease?

No. A restrictive pattern shows a normal or high ratio with reduced FVC.

Related Calculators

FEV1 FVC Ratio Calculator – Calculate FEV1/FVC ratio