Apnea-Hypopnea Index (AHI) Calculator

What is the Apnea-Hypopnea Index (AHI)?

AHI, or the Apnea-Hypopnea Index, shows how many apnea and hypopnea events occur per hour of sleep. This calculator uses the apnea count, hypopnea count, and total sleep time from a sleep study report to estimate adult AHI and place the result into a severity range you can read more easily.

It is useful when you want to double-check a reported AHI from raw counts or compare multiple study nights using the same calculation method. Still, AHI is only one part of the picture, and the meaning of the number can change depending on symptoms, oxygen levels, and how the study was scored.

When this tool can help

Sleep study reports often list several raw event counts and timing values that are not easy to interpret at a glance. This tool helps you calculate the index yourself, understand which adult range the result falls into, and organize better questions before speaking with a clinician.

• When you want to recalculate AHI from apnea count, hypopnea count, and total sleep time
• When you want to compare study results before and after treatment or between different nights
• When you want a quick guide to whether the number falls into a mild, moderate, or severe adult range
• When you need a simple way to explain the report to a family member or caregiver

Key features

The arithmetic behind AHI is simple, but the result is easier to understand when it is paired with adult severity ranges and a readable breakdown of the formula. That is why this tool combines a top result card, severity position, and an adult range table instead of showing only a single number.

• Instant AHI calculation from apnea count, hypopnea count, and total sleep time
• Top result card that highlights the AHI value and adult severity range first
• Severity bar and adult range table shown together for faster interpretation
• Notes about hypopnea scoring differences, testing method differences, and pediatric exclusion
• Sample input button so you can see the workflow immediately

How to use it

Take the raw numbers from a sleep study report and enter them in order. Add apnea count, hypopnea count, and the actual sleep time in hours and minutes, and the calculator will convert the study time into hours before computing the hourly event rate.

1. Enter apnea count: Add the number of events with complete airflow cessation.
2. Enter hypopnea count: Add the number of events with partial airflow reduction.
3. Enter total sleep time: Use the actual sleep time in hours and minutes.
4. Click Calculate: Check the AHI value, adult severity range, and highlighted table row.
5. Read the result in context: Use the number as a guide and interpret it together with the full report and clinical symptoms.

Details

Checked on: 2026-03-12 · Audience: for adult reference only · Pediatric reports need different thresholds

The core formula is AHI = (apnea count + hypopnea count) ÷ total sleep time in hours. For example, if there are 60 total events over 6 hours of sleep, the AHI is 10.0. In adults, the result is commonly described as normal range below 5, mild at 5–14.9, moderate at 15–29.9, and severe at 30 or above.

However, real sleep studies can produce different values from similar raw data depending on how hypopneas were scored. The result can shift depending on whether the scoring rule used a 3% or 4% oxygen desaturation threshold and whether arousals were included, so this tool should be used to understand a report, not to replace clinical interpretation.

• AASM-related source documents describe apnea and hypopnea burden as an hourly average.
• Public sources such as CMS and NICE also use adult AHI ranges as practical severity guides.
• Final decisions still depend on oxygen saturation, snoring severity, daytime sleepiness, comorbidities, and clinical assessment.

Frequently Asked Questions