How this calculator works
Use event counts scored by a sleep laboratory and the time actually asleep. Recording time from a home device gives a respiratory event index instead. The displayed bands are adult conventions; they do not establish a diagnosis and should not be applied to children. The result is an estimate for information only and is not medical advice.
Formula
AHI = (apnea events + hypopnea events) / sleep hours. Sleep hours = total events / AHI. A missing event count = AHI × sleep hours - the other count.
Worked example
30 apneas plus 60 hypopneas over 6 hours gives 90 / 6 = 15 events/hour. Ten plus twenty over 6 hours gives 5 events/hour.
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Frequently asked questions
Does time in bed equal sleep time?
No. Use measured sleep time for AHI; time awake changes the denominator.
Does this include respiratory effort-related arousals?
No. An RDI may include these additional events; AHI counts apneas and hypopneas.
What happens at 15 or 30?
This page uses 5 to below 15, 15 to below 30, and 30 or above for the adult bands. Your clinician also considers oxygen levels, symptoms and scoring rules.