How Much Sleep Did I Get?
Enter when you went to bed and when you woke up to see your actual sleep hours, cycle position, a REM estimate, and how it compares to your age-based target.
Your Sleep
When did you lie down to sleep?
When did you wake up?
Used to compare your sleep against your age-based target (defaults to the 7.5-hour adult recommendation).
Your Sleep Estimate
Enter when you went to bed and when you woke up, then click Calculate.
What Your Result Means
For educational purposes only — not medical advice.
How this calculator works: Your duration is the time from when you went to bed to when you woke up, minus about 15 minutes for falling asleep. Sleep runs in roughly 90-minute cycles through light, deep, and REM stages, so your total is also expressed in cycles. Waking in the middle of a cycle — especially during deep sleep — triggers sleep inertia, the groggy, disoriented feeling right after waking; waking near a cycle boundary is cleaner and leaves you more refreshed.
Duration matters: The National Sleep Foundation recommends 7 to 9 hours for adults aged 18 to 64. Consistently sleeping fewer than 6 hours is associated with a 12% increase in all-cause mortality risk, based on a meta-analysis of 1.3 million subjects (Cappuccio et al. 2010). Chronic short sleep also raises cardiovascular disease risk and impairs cognitive performance and immune function.
Quality matters as much as duration. To improve sleep quality: keep a consistent wake time (vary by no more than 30 minutes, even on weekends), keep your bedroom cool at 65 to 68 degrees F (18 to 20 degrees C), avoid screens for 30 to 60 minutes before bed, and limit caffeine after early afternoon.
| Age Group | NSF Recommended Sleep | Minimum |
|---|---|---|
| Teenagers (14–17) | 8–10 hours | 7 hours |
| Young Adults (18–25) | 7–9 hours | 6 hours |
| Adults (26–64) | 7–9 hours | 6 hours |
| Older Adults (65+) | 7–8 hours | 5 hours |
Hours slept = (Wake time − Bed time) − 15 min (sleep-onset latency)
Cycle position: Duration ÷ 90 min — waking on a whole-cycle boundary is the cleanest point. REM ≈ 20–25% of the night, weighted toward the later cycles.
Age target: NSF recommends 8–10h for teens, 7–9h for adults 18–64, 7–8h for adults 65+.
Limitations
Individual sleep needs vary; the optimal amount differs by genetics (some people are genuine short sleepers). Sleep cycle length averages 90 minutes but ranges from 80–120 minutes between individuals. This calculator assumes average sleep-onset latency of 15 minutes — those with insomnia or poor sleep hygiene may need to adjust. Sleep quality (depth of slow-wave sleep, REM proportion) matters as much as duration. The REM figure is an estimate, not a measurement.
✓ Strong EvidenceWant to learn more? Read our in-depth article: How Much Sleep Do You Actually Need? →
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