Set your wake-up time and how much sleep you want, and get the bedtime that delivers it, with the 15 minutes to fall asleep already counted.
| Input | Result |
|---|---|
| Wake at 7:00 AM, want 8 h | Bed at 10:45 PM |
| Wake at 6:00 AM, want 7 h | Bed at 10:45 PM |
| Wake at 8:00 AM, want 9 h | Bed at 10:45 PM |
| Age group | Recommended sleep |
|---|---|
| Adult (18-60 years) | 7 or more hours |
| Older adult (65+) | 7-8 hours |
| Teen (13-17 years) | 8-10 hours |
| School age (6-12 years) | 9-12 hours |
| Preschool (3-5 years) | 10-13 hours |
| Toddler (1-2 years) | 11-14 hours |
| Infant (4-11 months) | 12-16 hours |
| Newborn (0-3 months) | 14-17 hours |
You do not fall asleep the moment you get into bed. Sleep latency for a healthy adult is typically 10–20 minutes, so every bedtime this calculator returns has 15 minutes built in. Planning to be asleep at 11:00 PM therefore means getting into bed at about 10:45 PM. Falling asleep in under five minutes is not a sign of good sleep — it usually means you are sleep-deprived.
Time in bed also is not the same as time asleep. Brief awakenings through the night (1–3 is normal, a few minutes each) mean a full night in bed usually yields 30–60 minutes less actual sleep, so if you need 7.5 hours of sleep, plan roughly 8 hours in bed.
Your circadian clock is anchored mostly by when you wake and when you first see bright light, not by when you go to bed. That is why keeping the wake time fixed and moving the bedtime is easier than the reverse — and why a consistent bedtime within about 30 minutes night to night matters more than chasing an extra half hour once a week.
If you are trying to move your bedtime earlier, shift it 15–20 minutes at a time every few nights rather than by an hour at once, and keep the wake time where it is. Bright light within the first hour after waking pushes the clock earlier; bright light late in the evening pushes it later.
It depends on your wake-up time and how much sleep you need. For a 7:00 AM alarm and 7–9 hours of sleep, the window runs from 9:45 PM to 11:45 PM once 15 minutes to fall asleep is included.
Wake time. Bright light on waking is the strongest signal that sets the circadian clock, so a fixed wake time stabilises sleep more effectively than a fixed bedtime.
Total sleep matters most in the short term, but a bedtime that runs against your circadian rhythm produces 'social jetlag' — the same groggy feeling as flying a time zone. Consistency of both ends is the goal.
Keep the room cool (about 18–19°C / 65–67°F), avoid bright screens for the last hour, avoid caffeine after early afternoon (its half-life is 5–6 hours) and avoid alcohol in the three hours before bed — it shortens the time to fall asleep but fragments the second half of the night.
Use it as a target for whenever your main sleep block starts, and treat that block as your fixed 'night'. Shift workers often need to split sleep into two blocks; plan the longer block with this calculator.