AHI Calculator
Compute apnea-hypopnea index from apnea episodes, hypopnea episodes, and sleep time.
What Is the Apnea-Hypopnea Index?
The apnea-hypopnea index (AHI) measures sleep-disordered breathing severity by counting apnea and hypopnea events per hour of sleep. It is the primary metric from polysomnography and home sleep tests. Related tools: 6 Minute Walk Test Calculator and AA Gradient Calculator.
AHI Formula
$$AHI = \frac{Apnea + Hypopnea}{Sleep\ time\ (minutes)} \times 60$$
Result is events per hour. Normal is below 5, mild is 5–14, moderate is 15–29, and severe is 30 or higher.
Frequently Asked Questions
What counts as an apnea event?
An apnea is a complete cessation of airflow for at least 10 seconds during sleep.
What counts as a hypopnea?
A hypopnea is a partial reduction in airflow (typically at least 30%) with associated oxygen desaturation or arousal.
What AHI is considered normal?
An AHI below 5 events per hour is generally considered normal in adults.
How much sleep time should I enter?
Use total sleep time from your sleep study report, not time in bed. Seven hours equals 420 minutes.
Does AHI alone determine treatment?
No. Symptoms, comorbidities, and oxygen levels also guide CPAP or other therapy decisions.
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