ISI: Insomnia Severity Index

Brief screening measure for insomnia severity and outcomes. ≈ 2 min to complete. Free with attribution.

sleep 7 items ≈ 2 min Updated 2026-05-06

Score ISI below → Download printable PDF View source paper (DOI)
What is ISI? ISI (Insomnia Severity Index) is a validated instrument used to assess brief screening measure for insomnia severity and outcomes.. It is used in brief screening measure for insomnia severity and outcomes.. It comprises 7 items. Administration takes about 2 min.

What is ISI?

ISI (Insomnia Severity Index) is a validated clinical instrument used to assess brief screening measure for insomnia severity and outcomes.. It is most often used for brief screening measure for insomnia severity and outcomes.. The instrument contains 7 items. Typical administration time is ≈ 2 min.

Source / attribution: Free to use with citation

Clinical context: when ISI is used

Brief screening measure for insomnia severity and outcomes. ISI is part of standard practice in this setting because it provides a structured, replicable assessment that can be tracked over time and compared across patients or visits.

Like all screening or assessment instruments, ISI is a structured aid — not a diagnostic test in isolation. Results should be interpreted alongside history, examination, and clinical context. Where a score crosses an actionable threshold, the next step is typically a more detailed clinical evaluation rather than a definitive diagnosis.

Score ISI

Answer all 7 items below to see your ISI score and interpretation.

Each item is scored on a 5-point scale (0–4). Your score updates live as you answer.

All scoring runs in your browser. No data is sent anywhere — close the tab and the answers are gone.

How ISI is scored

Sum all 7 items scored 0-4. Total range 0-28.

Scoring notes: Sum all 7 items scored 0-4. Total range 0-28.

ISI score interpretation

The cutoffs below are drawn from the published validation literature. Always interpret in clinical context.

Score rangeBandInterpretation
0–7No clinically significant insomniaNone
8–14Subthreshold insomniaSleep hygiene education
15–21Moderate insomniaConsider treatment
22–28Severe insomniaActive treatment

How to score ISI: a step-by-step worked example

This is an illustrative walkthrough, not a real patient. Follow the same four steps with your own answers — or use the live calculator at the top of this page.

Step 1 — Score each item

Read each question and choose the response that best fits. Each response has a number next to it — that number is the item's score. The example below uses illustrative answers.

#ItemExample responseScore
1Difficulty falling asleepSevere3
2Difficulty staying asleepModerate2
3Problem waking up too earlySevere3
4How satisfied/dissatisfied are you with your current sleep patternModerately satisfied2
5How noticeable to others do you think your sleep problem is in terms of impairing the quality of your lifeMuch3
6How worried/distressed are you about your current sleep problemSomewhat2
7To what extent do you consider your sleep problem to interfere with your daily functioningMuch3

Step 2 — Add up the scores

Add up all the item scores you noted in Step 1.

3 + 2 + 3 + 2 + 3 + 2 + 3 = 18

Step 3 — Look up the band

Find the row in the interpretation table whose range contains your total:

Total = 18 falls between 15 and 21Moderate insomnia

Step 4 — What does this mean clinically?

Moderate insomnia. Consider treatment

A score is one input alongside history and examination. ISI supports clinical judgment — it does not replace it.

Score ISI with your own answers above →

ISI psychometric properties

Psychometric figures are drawn from the validation literature and may vary across clinical populations and translations.

Limitations & common pitfalls

How ISI compares to other sleep scales

If ISI doesn't fit your context, related instruments in sleep include:

ScaleMeasuresItemsTime
PSQI19-item measure assessing sleep quality and disturbances over one month.7≈ 5 min
ESS8-item questionnaire measuring daytime sleepiness in everyday situations.8≈ 2 min
AIS8-item scale based on ICD-10 insomnia criteria for clinical assessment.8≈ 2 min
PHQ-9Severity of depression9≈ 3 minutes
GAD-7Severity of generalized anxiety7≈ 2 minutes
AUDIT10-item WHO screening tool for hazardous alcohol consumption and dependence.10≈ 3 min
CHA2DS2-VAScAnnual stroke risk in non-valvular atrial fibrillation8
Glasgow Coma ScaleLevel of consciousness after head injury3

Frequently asked questions about ISI

What does ISI measure?

ISI (Insomnia Severity Index) is a validated instrument that assesses brief screening measure for insomnia severity and outcomes.. Its primary clinical use is brief screening measure for insomnia severity and outcomes..

How long does ISI take to complete?

ISI typically takes ≈ 2 min to administer. Time can vary slightly depending on whether it is self-administered or clinician-led.

How many items are on ISI?

ISI contains 7 items. Items are summed to produce a total score.

What is a high ISI score?

Scores of 22–28 fall in the "Severe insomnia" band. Active treatment

What is a low ISI score?

Scores of 0–7 fall in the "No clinically significant insomnia" band. None

How reliable is ISI?

ISI has reported Cronbach's α of 0.9 in validation samples and test–retest reliability of 0.87. Correlates with sleep diaries and polysomnography.

Is ISI free to use?

ISI is free to use with attribution. Free to use with citation

What is the source paper for ISI?

Bastien, C. H., Vallieres, A., & Morin, C. M. (2001). Validation of the Insomnia Severity Index. Sleep, 24(2), 297-298.

Can ISI replace clinical judgment?

No. ISI is a structured assessment aid. A score is one input alongside history, examination, and clinical context. Treatment decisions should never rest on a screening score alone.

References & validation

ISI is supported by the following peer-reviewed sources: