11 p.m. to 7 a.m. — How Many Hours of Sleep?
The exact math on the 11 p.m. – 7 a.m. schedule: time in bed vs. actual sleep vs. sleep cycles, plus a checker for any bedtime and wake-up combination.
11 p.m. to 7 a.m. — The Math
From 11:00 p.m. to 7:00 a.m. is exactly 8 hours in bed. The average person takes about 15 minutes to fall asleep, leaving roughly 7.75 hours of actual sleep, which is just past 5 complete 90-minute sleep cycles. That's inside the 7–9 hour range recommended for adults — one of the best realistic schedules a student can run.
| Schedule | Time in bed | Actual sleep | Cycles |
|---|---|---|---|
| 11 p.m. → 7 a.m. | 8.0 h in bed | ≈7.75 h asleep | 5.2 |
| 11 p.m. → 6 a.m. | 7.0 h in bed | ≈6.75 h asleep | 4.5 |
| 10 p.m. → 6 a.m. | 8.0 h in bed | ≈7.75 h asleep | 5.2 |
| 10 p.m. → 7 a.m. | 9.0 h in bed | ≈8.75 h asleep | 5.8 |
| 12 a.m. → 7 a.m. | 7.0 h in bed | ≈6.75 h asleep | 4.5 |
| 12 a.m. → 8 a.m. | 8.0 h in bed | ≈7.75 h asleep | 5.2 |
| 1 a.m. → 8 a.m. | 7.0 h in bed | ≈6.75 h asleep | 4.5 |
| 9:30 p.m. → 6:30 a.m. | 9.0 h in bed | ≈8.75 h asleep | 5.8 |
In Bed vs. Asleep — Why the Difference Matters
Sleep trackers and sleep math both distinguish time in bed from sleep duration. Falling asleep takes ~10–20 minutes for most people (longer with late caffeine or screens), and brief awakenings during the night shave off more. A clean "8 hours" of bed time usually nets 7.5–7.75 hours of sleep — which is why the 11-to-7 schedule works so well: it has a built-in buffer that still lands you above 5 cycles.
Getting More Out of the Same 8 Hours
Keep the wake time fixed — 7 a.m. on weekends too, within an hour. Cut caffeine roughly 8–10 hours before bed (the caffeine calculator gives your personal cutoff based on dose and timing). And if you consistently feel groggy at 7 a.m. despite a full night, shift bedtime by ±15 minutes for a week — you're likely waking mid-cycle, and a small shift lands the alarm on a boundary. For other schedules, the sleep calculator handles any bedtime/wake-time combination.