The Insomnia Severity Index is the standard seven item questionnaire for grading insomnia, covering night symptoms, daytime impact and distress. Scores run from zero to twenty eight, with fifteen marking the boundary of clinical insomnia. Answer the seven questions as the past two weeks have actually been, and the total maps onto the validated severity bands.
Your visual report appears here
Fill in the form and press Calculate. You will get your number, an interpretation chip, and a personalized chart pack drawn instantly in your browser.
- Risk spectrum with your position marked
- Reference ranges from the original publication
- Shareable link, nothing stored
Scientific references
Insomnia is a diagnosis of degree, and degrees need a ruler. Developed at Laval University and validated against sleep diaries and laboratory studies, the Insomnia Severity Index became that ruler, now the most used insomnia measure in trials and clinics worldwide.
What the Seven Items Capture
Three questions grade the night itself, trouble falling asleep, staying asleep and waking too early. The remaining four grade the fallout, satisfaction with sleep, daytime interference, how obvious the problem is to others and how much it worries you. Each scores zero to four, and the final four items are what lift the ISI beyond a simple sleep diary into a measure of the disorder’s real weight.
The Bands
Zero to seven means no significant insomnia. Eight to fourteen is subthreshold, a zone where sleep hygiene fixes and stress work often suffice. Fifteen to twenty one is moderate clinical insomnia, the level where cognitive behavioral therapy for insomnia earns its first line status in every major guideline. Twenty two and above marks severe insomnia, where professional help should not wait.
Why CBT-I Beats Pills
Medication helps nights but not the disorder, and tolerance builds. CBT-I, combining stimulus control, sleep restriction and cognitive work on catastrophic sleep beliefs, matches pills in the short term and beats them durably after treatment ends. The ISI doubles as the progress ruler inside that therapy, with a drop of six or more points counting as a meaningful response.
Repeat the questionnaire every few weeks under any treatment plan. Trend matters more than any single score, and improvement often shows on the ISI before it is felt subjectively.