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Spirometry Interpretation Calculator

Work out spirometry interpretation instantly with clear inputs, formula shown and shareable results.

About Spirometry Interpretation Calculator

Combines the FEV1/FVC ratio with percent-predicted FEV1 and FVC to name the pattern and grade severity on the GOLD scale.

Formula

Pattern and grade

Ratio <70% indicates obstruction; FVC <80% predicted with a normal ratio suggests restriction. GOLD grades: 1 >=80%, 2 50-79%, 3 30-49%, 4 <30% predicted FEV1

Worked example

With the default values below, Spirometry Interpretation Calculator returns Spirometry pattern of Obstructive pattern. Change any input above and every figure here is recalculated in your browser.

Inputs used

FEV1 as percent of predictedaccepts 10–150 %
72 %
FVC as percent of predictedaccepts 10–150 %
88 %
FEV1/FVC ratioaccepts 20–100 %
65 %

Results

Spirometry pattern
Obstructive pattern
GOLD severity grade
Moderate (50-79%)
Grade number
2

Step by step

  1. 1Values used
  2. 2Pattern and grade
  3. 3Spirometry pattern= Obstructive pattern
  4. 4GOLD severity grade= Moderate (50-79%)
  5. 5Grade number= 2

Assumptions and limits

  • The result is derived only from the 3 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 whole numbers, 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

Should values be post-bronchodilator?

Yes. GOLD grading uses post-bronchodilator spirometry to confirm persistent airflow limitation.

Can spirometry alone diagnose restriction?

No. True restriction needs lung volume measurement; low FVC only suggests it.

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