The Stanford Sleepiness Scale (SSS) is a quick check of how awake or sleepy you feel right now. It asks you to choose one of seven statements, from energetic and fully alert at 1 to close to falling asleep at 7. Unlike a questionnaire about the past week, it captures a single moment. That makes it useful for recording changes across a day, before and after a task, or during a sleep study. It remains a subjective rating: the score describes your perception and does not diagnose a sleep disorder or prove that an activity is safe.
Stanford Sleepiness Scale Calculator
Record the one-to-seven Stanford Sleepiness Scale description that best matches current alertness.
Current state
SSS
Choose one description
Scale summary
Selected score
The selected score will appear here
Choose the statement that best represents how you feel right now.
Stanford Sleepiness scoreSelected description mapped to a score from 1 to 7
- Selected score
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- Scale direction
- Higher means sleepier
- Page message
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Educational estimate only. It is not medical advice, a diagnosis, or a substitute for assessment by a qualified healthcare professional. This momentary self-rating does not diagnose a sleep disorder or establish safety for driving or hazardous work.
Table of Contents
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What is Stanford Sleepiness Scale?
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How to Use This Calculator
- Pause and judge your present state, rather than how you felt this morning or how you usually sleep.
- Read all seven choices. Select the one that most closely describes your alertness at this moment, even if two neighboring statements seem plausible.
- Choose Calculate to translate the selected statement into its score from 1 through 7.
- If you are keeping a log, record the score with the time, recent sleep, medication, caffeine, work shift, and activity. Those details make repeated scores more meaningful.
Use the scale under similar conditions when comparing readings. A score taken while lying quietly in a dark room is not directly comparable with one taken after walking outdoors. Do not repeatedly change an answer to obtain a preferred number; the first careful choice is usually the clearest record of how you felt.
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Formula Used
No arithmetic is required. The selected description maps directly to an integer:
SSS score = assigned value of the chosen statement, from 1 to 7.
Lower values describe greater alertness and higher values describe greater sleepiness. The scale is ordinal. A score of 6 is higher than 3, but it should not be interpreted as exactly twice as sleepy. It also has no conversion to hours of sleep.
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Variables Explained
| Item | Meaning |
|---|---|
| Current feeling | The one statement that best matches alertness or sleepiness at the moment of rating. |
| Score 1 | Feeling active, vital, alert, and wide awake. |
| Scores 2–3 | Still functioning at a high level, though score 3 reflects being relaxed and less fully alert. |
| Scores 4–5 | Increasingly foggy, slowed, or reluctant to remain awake. |
| Scores 6–7 | Marked sleepiness, with a strong wish to lie down or sleep onset approaching. |
| Time and context | Useful notes for comparing repeated ratings; they do not change the numeric score. |
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Worked Example
Suppose you choose the fourth statement because you feel somewhat foggy and let down, although you can continue what you are doing. The selected statement has an assigned value of 4, so the displayed score is 4. No averaging or adjustment is applied. If you repeat the check later and choose the sixth statement, that later score is 6. The change from 4 to 6 records greater perceived sleepiness under the later conditions; by itself, it does not explain why the change occurred.
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Why Use This Calculator?
Read the result as a description of one point in time. A low value suggests that you felt alert when you answered. A middle value reflects reduced alertness or fogginess. A high value signals pronounced subjective sleepiness. Context matters: insufficient sleep, shift work, illness, sedating medicines, alcohol, time of day, and a quiet setting can all affect the answer.
A single rating cannot establish a medical condition. Repeated high scores, unplanned sleep episodes, loud snoring with breathing pauses, or sleepiness that disrupts work or daily life are reasons to discuss the pattern with a qualified healthcare professional. Never use a favorable score as permission to drive or operate machinery. If you are struggling to stay awake, stop the safety-sensitive activity and use a safe alternative.
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Common Mistakes
- Answering for a typical day instead of the present moment changes what the scale measures.
- Choosing a lower score because an important task must be completed hides the symptom rather than changing it.
- Treating equal score gaps as exact equal changes overstates the precision of an ordinal scale.
- Comparing readings taken in very different settings can make an ordinary environmental effect look like a trend.
- Using the score alone to diagnose insomnia, sleep apnea, narcolepsy, or another disorder is inappropriate.
- Confusing this seven-point scale with another sleepiness questionnaire can lead to incorrect interpretation.
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Frequently Asked Questions
Is the Stanford Sleepiness Scale a diagnosis?
No. It is a brief subjective rating of current alertness. A clinician may consider it alongside symptoms, sleep history, examination, or testing, but the number alone does not identify a disorder.
When should I complete the scale?
Complete it at the moment you want to assess, before looking back at earlier answers. For a diary, use planned times and note the circumstances so later comparisons have context.
What does a score of 4 mean?
It corresponds to the fourth statement and reflects a somewhat foggy or let-down feeling. It is a middle point on this scale, not a universal boundary between safe and unsafe performance.
Can caffeine change the score?
It can change how alert a person feels. Record recent caffeine use if you are comparing ratings, because dose, timing, tolerance, and sleep loss may all influence the response.
Can I use a low score to decide whether to drive?
No. A self-rating cannot guarantee safe reaction time or prevent microsleeps. If you feel drowsy or have trouble staying awake, do not drive and arrange a safe alternative.
Why might my score change during the day?
Alertness normally varies with sleep pressure, body clock timing, activity, light, meals, medicines, illness, and recent sleep. A log can help show whether a pattern repeats.
Should I average several SSS scores?
A researcher or clinician may summarize a planned series, but a simple average can hide when severe sleepiness occurred. Keep the individual time-stamped values as well as any summary.
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Sources & References
Scale wording and intended momentary use are described by the American Thoracic Society. The seven response levels are also reproduced in the University of Pennsylvania scale sheet. For clinical background on subjective sleepiness measures, see the National Academies review hosted by NCBI.