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Apnoea Hypopnoea Index Calculator

Work out apnoea hypopnoea index instantly with clear inputs, formula shown and shareable results.

About Apnoea Hypopnoea Index Calculator

Divides the total number of apnoeas and hypopnoeas by hours of sleep to give the apnoea-hypopnoea index used to grade sleep apnoea severity.

Formula

AHI

AHI = (apnoeas + hypopnoeas) / total sleep time in hours; mild 5-14.9, moderate 15-29.9, severe 30 or more

Worked example

With the default values below, Apnoea Hypopnoea Index Calculator returns Apnoea-hypopnoea index of 15.4. Change any input above and every figure here is recalculated in your browser.

Inputs used

Apnoea eventsaccepts 0–2,000
40
Hypopnoea eventsaccepts 0–2,000
60
Total sleep timeaccepts 0.5–14 h
6.5 h

Results

Apnoea-hypopnoea index
15.4 events/h
Severity band
Moderate range
Total respiratory events
100

Step by step

  1. 1Values used
  2. 2AHI
  3. 3Apnoea-hypopnoea index= 15.4 events/h
  4. 4Severity band= Moderate range
  5. 5Total respiratory events= 100

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 1 decimal place, 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

Is AHI the same as RDI?

No. The respiratory disturbance index also counts respiratory effort related arousals, so it is usually higher.

Does home testing give the same value?

Home studies use recording time rather than measured sleep time, which tends to underestimate the index.

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