Insomnia Severity Calculator — See Your ISI Score Now

Waking at 3 a.m. and staring at the ceiling is one of the most common sleep complaints there is — and it’s also one of the most measurable. About 15.4% of US adults reported trouble falling asleep most days or every day in 2024, and 18.1% reported trouble staying asleep, according to a 2026 CDC data brief drawing on national health survey data (Short Sleep Duration and Sleep Difficulties Among Adults, 2026). That’s a big chunk of the country lying awake, and it’s exactly the gap the Insomnia Severity Index was built to measure.

This calculator uses the same 7-item questionnaire sleep researchers have relied on for more than three decades. Answer honestly about the past two weeks, and you’ll get a score from 0 to 28, plus a plain-language read on what that number means for your daily life — not just a clinical label with no context attached.

What The Insomnia Severity Index Actually Measures

The Insomnia Severity Index is a 7-question self-report tool that captures both how bad your sleep problem feels and how much it’s bleeding into your daytime life. Charles Morin, a psychologist at Université Laval in Quebec, first published it in 1993 as a way to track how patients responded to treatment over time — not just to slap a label on them.

What makes the ISI different from simply asking “how many hours did you sleep?” is that it weighs severity, satisfaction, and daytime impact together. Two people can sleep the same number of hours and land on very different scores, because one feels fine the next day while the other is exhausted and irritable at work. That’s the point. Insomnia, clinically, isn’t really about hours in bed — it’s about the gap between what you need and what you’re getting, and how much that gap costs you.

Bastien, Vallières, and Morin formally validated the tool in 2001 in the journal Sleep Medicine, testing it against structured clinical interviews in real patients. A follow-up validation by Morin and colleagues, published in 2011 in the journal Sleep, found that a cutoff score of 10 correctly identified insomnia cases with 86.1% sensitivity and 87.7% specificity when checked against community samples. In plain terms: if the ISI says you likely have insomnia, it’s right about 86 to 88% of the time — good enough that clinicians still use it as a first-pass screen before a full diagnostic workup.

Reading Your Score: What Each Band Means

An ISI score on its own is just a number — what matters is which of four bands it falls into, since each one calls for a different response.

Why Insomnia Happens: The 3P Model

Sleep researchers generally explain chronic insomnia using the 3P model — predisposing, precipitating, and perpetuating factors. It’s a useful lens because it separates “why me” from “why now” from “why won’t it stop.”

Here’s the thing though — that third category is where CBT-I does most of its work. You can’t undo the layoff or the loss that started the insomnia. But you can undo the habits your brain picked up while trying to cope with it.

CBT-I: What The Research Actually Shows

Cognitive behavioral therapy for insomnia, or CBT-I, is the first-line treatment recommended by the American Academy of Sleep Medicine, and it isn’t a vague “relax more” suggestion — it’s a structured, several-week program built around specific behavior changes.

A 2024 study comparing initial treatment choices for chronic insomnia found that patients who started with CBT-I had better long-term remission outcomes than those who began on sleep medication, with combination therapy offering only a marginal edge over CBT-I alone (PubMed, 2024). That’s worth sitting with — the therapy without pills outperformed the pills, at least for durable, long-term results.

A separate 2025 systematic review and meta-analysis examining CBT-I across people with chronic diseases found consistently moderate-to-large effect sizes, and noted the treatment held up about as well in people managing other health conditions as in people without them (systematic review, 2025). Here’s what this means for you: CBT-I isn’t just for “textbook” insomnia cases — it tends to help broadly, even when sleep problems are tangled up with other health issues.

The Five Core Components of CBT-I

Acute vs. Chronic: Not The Same Problem

A rough night before a big presentation isn’t the same condition as insomnia that’s dragged on for months, even though both feel miserable in the moment. Telling them apart matters, because the right response differs for each.

Notice that acute insomnia often looks identical to subthreshold insomnia on a single ISI reading. The real tell is time — if two weeks pass and the score hasn’t budged even after the original stressor is gone, that’s the signal it’s shifted from a passing rough patch into something perpetuating itself.

A Reader Scenario: Recognizing The Pattern

Common Myths About Insomnia

It’s easy to pick up bad advice about sleep, mostly because so much of it sounds intuitive. A few of the most persistent myths are worth clearing up.

• “Lying in bed resting is better than nothing” — actually, extended time awake in bed trains your brain to associate the bed with wakefulness, which is exactly what stimulus control therapy tries to undo.
• “You can catch up on sleep debt over the weekend” — some recovery happens, but sleeping in erratically disrupts your circadian rhythm and often makes the following week’s sleep worse, not better.
• “Insomnia means you need medication” — sleep medication can help short-term, but CBT-I has shown more durable results at 6- and 12-month follow-up in multiple trials.
• “Older adults just need less sleep” — needs decrease modestly with age, but chronic dissatisfaction with sleep at any age is still worth addressing, not written off as normal aging.

When To See A Doctor

Insomnia is common, and mild versions of it are rarely an emergency — but a few signals mean it’s time to loop in a professional rather than just pushing through.

Putting Your Score To Work

A single ISI score is a snapshot, not a verdict. What matters more is the trend — retake the assessment every couple of weeks if you’re making changes, and watch whether the number moves in the direction you’d expect. If you’ve started a sleep hygiene routine and your score hasn’t budged after a month, that’s useful information: it suggests the problem needs a more structured approach like CBT-I rather than more tweaks to bedtime habits.

It’s also worth pairing this assessment with a look at your actual sleep timing, since severity and timing are related but distinct problems. Our Sleep Cycle Calculator can help you find a bedtime that lines up with natural 90-minute sleep cycles, which is a useful companion step once the insomnia itself is being addressed. And if shift work or irregular hours are part of the picture, the Circadian Rhythm Calculator digs into timing misalignment specifically, which often masquerades as insomnia when it’s really a scheduling problem. If you’re also tracking accumulated sleep loss, the Sleep Debt Calculator pairs well with this assessment.

None of this replaces a conversation with a doctor once your score crosses into moderate or severe territory. But for the subthreshold range, tracking your number over time while you experiment with sleep hygiene changes is a genuinely useful way to see what’s working before escalating to a clinical referral.

Frequently Asked Questions