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The Apnea-Hypopnea Index (AHI) is the standard measure reported from a sleep study, calculated as the number of apnea and hypopnea events divided by total sleep hours, classified against the American Academy of Sleep Medicine (AASM) severity bands: normal below 5, mild 5-15, moderate 15-30, severe above 30. This calculator simply re-derives the index from raw event counts — it is a reference calculation, not a diagnostic replacement for a physician's interpretation of an actual sleep study. Consult a doctor or sleep specialist for an actual diagnosis.
How it works
Enter the number of apnea events, hypopnea events, and total sleep hours from a sleep study. The tool sums the events, divides by sleep hours, and classifies the result against the standard AASM severity bands.
- Enter apnea events (count).
- Enter hypopnea events (count).
- Enter total sleep hours.
- Click Calculate to see your results.
Examples
20 apnea + 15 hypopnea events over 7 hours
AHI = 35 / 7 = 5.0, at the boundary between normal and mild.
Who should use it
- Double-checking an AHI calculation from a sleep study report.
- Understanding what a reported AHI severity classification means.
Industry applications
- Sleep medicine and diagnostics
- Patient education
Advantages
- Quick way to re-check or re-derive an AHI figure from raw event counts.
- Uses the standard, widely recognized AASM severity classification.
Limitations
- Does not replace an actual sleep study or a physician's interpretation.
- A single index number omits other clinically relevant details from a full sleep study.
Common mistakes to avoid
- Using this calculator as a substitute for an actual sleep study rather than for re-deriving the index from existing study data.
- Ignoring that a single AHI number doesn't capture other clinically relevant details like oxygen desaturation levels.
Best practices
- Always have AHI results interpreted by a physician or sleep specialist alongside the rest of a full sleep study report.
Tips
- Discuss your full sleep study report, not just the AHI number, with a sleep specialist for a complete picture.