ToolsCalculators
Stanford Sleepiness Scale (SSS)
Self-rated level of alertness/sleepiness at a moment in time.
Stanford Sleepiness Scale (SSS)
Current state that best describes you right now
Result1 of 7
Alert range: acceptable daytime alertness.
- SSS level
- 1 of 7
When to use
- Quantifying a person's subjective sleepiness at a single moment, e.g. before/after an intervention or across the day.
- Tracking state alertness in sleep research or vigilance/shift-work assessment.
Formula
Single self-selected level from 1 (fully alert) to 7 (sleep onset imminent). Higher = sleepier. Reflects state at the moment of rating, not habitual sleepiness.
Pearls and pitfalls
- Measures momentary state, not trait sleepiness; repeat across the day to capture fluctuation.
- Levels 1-3 are considered the alert range; 4 or higher indicates degraded alertness.
- Unlike the Epworth Sleepiness Scale, the SSS does not estimate chronic daytime sleep propensity.