Enter your apnea episodes, hypopnea episodes, and total sleep time (in hours and minutes) to calculate your Apnea-Hypopnea Index (AHI). You'll get your AHI score in events per hour along with a severity classification — Normal, Mild, Moderate, or Severe sleep apnea — based on standard clinical thresholds.
AHI Score
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Severity Classification
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Total Respiratory Events
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Total Sleep Time
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The Apnea-Hypopnea Index (AHI) is a standardized measure used to assess the severity of sleep apnea. It represents the average number of apnea (complete breathing pauses) and hypopnea (shallow breathing) events that occur per hour of sleep. A higher AHI score indicates more severe sleep-disordered breathing.
AHI is calculated using the formula: AHI = (Total Apnea Episodes + Total Hypopnea Episodes) ÷ Total Sleep Time in Hours. For example, if you had 60 combined events over 7.5 hours of sleep, your AHI would be 8 events per hour, placing you in the mild sleep apnea range.
For adults, an AHI below 5 events per hour is considered normal. A score of 5–14.9 indicates mild sleep apnea, 15–29.9 indicates moderate sleep apnea, and 30 or above indicates severe sleep apnea. Treatment decisions are typically based on these thresholds along with a patient's overall symptoms and health history.
Yes. For pediatric patients, the threshold for abnormal AHI is lower. An AHI greater than 1 event per hour is generally considered abnormal in children. A score above 5 in children is often classified as moderate-to-severe and may warrant more aggressive treatment.
When using CPAP therapy, a residual AHI below 5 events per hour is generally considered a good outcome, indicating effective treatment. Many sleep specialists aim for an AHI below 2 during CPAP use. If your CPAP AHI remains elevated, your device pressure settings may need adjustment.
A high AHI score is associated with significantly elevated risk for serious health conditions including hypertension, stroke, heart attack, type 2 diabetes, and even neurodegenerative diseases like Parkinson's. Untreated severe sleep apnea also contributes to excessive daytime sleepiness, cognitive impairment, and reduced quality of life.
AHI is typically measured during a polysomnogram (PSG) — a comprehensive overnight sleep study conducted in a clinic — or a home sleep apnea test (HSAT). Sensors monitor breathing effort, airflow, blood oxygen levels, and sleep stages to count and categorize each respiratory event throughout the night.
AHI has limitations as a standalone metric. It does not capture the duration or severity of individual events, blood oxygen desaturation levels, or the impact on sleep quality. Two patients with identical AHI scores can have very different clinical presentations. Physicians typically consider AHI alongside symptoms, oxygen levels, and overall patient health.