Free CPAP tool
Sleep Apnea Severity from AHI
Enter an AHI from your sleep study report and see which adult severity band it falls in. The output is a number from 0 to 3; the mapping is explained below. Your diagnosis comes from the clinician who read your study, not from this number alone.
Formula
Mapping used for adults (the AASM 1999 task force bands): 0 = normal, AHI under 5. 1 = mild, 5 to under 15. 2 = moderate, 15 to under 30. 3 = severe, 30 or more.
The second output shows how far the number is below the next band; it is 0 in the severe band. Medicare uses its own thresholds for CPAP coverage: an AHI of 15 or more, or 5 to 14 with certain symptoms or conditions such as hypertension or a history of stroke.
Worked example
AHI 10: it is not under 5, but it is under 15, so severity = 1 (mild). Events to the next band = 15 minus 10 = 5. AHI 32 gives 3 (severe) and 0.
Assumptions and limits
- Adult thresholds only; children are judged differently.
- The band does not capture oxygen levels, symptoms or other findings your clinician weighs.
- Use the diagnostic AHI from a sleep test, not a nightly CPAP reading.
Only a sleep test can tell. Home sleep tests are a common first step for adults without other major health conditions; your doctor can order one, or you can use an online service that includes a clinician review.
Frequently asked questions
Is an AHI of 10 bad?
An AHI of 10 is in the mild band for adults. Whether to treat depends on symptoms and other health factors, which is a decision for your sleep clinician. Medicare covers CPAP at that level only with documented symptoms or conditions.
What AHI is severe sleep apnea?
30 or more events per hour is the severe band in adults. Severe sleep apnea is a reason to start treatment promptly and keep follow-up appointments.
Does Medicare cover CPAP for mild sleep apnea?
Medicare's policy covers an AHI of 5 to 14 only with documented excessive sleepiness, cognitive or mood problems, insomnia, hypertension, heart disease or a history of stroke. An AHI of 15 or more qualifies on its own.
Sources
Last reviewed October 11, 2026. How we research · Report an error