Updated
To plan a bedtime, subtract your intended sleep duration and your allowance for falling asleep from your wake time. Subtract wind-down time separately to see when to start getting ready. The result reserves time in your schedule; it does not predict when you will fall asleep, wake refreshed or finish a sleep cycle.
How to plan your bedtime
- 1Choose a direction: enter a wake time to find bedtime, or a bedtime to find wake time. Set your actual sleep target; eight hours is an editable starting assumption.
- 2Allow time to fall asleep. The default is twenty minutes, but use an estimate that fits your recent experience rather than treating it as a required duration.
- 3Optionally add wind-down time. The thirty-minute default moves preparation earlier without counting it as sleep. Read the day label if the plan crosses midnight.
How wake time becomes a bedtime plan
Planned bedtime = wake time minus sleep target minus time to fall asleep. In reverse, wake time = bedtime plus time to fall asleep plus sleep target. Wind-down starts before bedtime and is excluded from the sleep target.
Sleep needs differ between people. The calculation does not choose your target from your age or health. It also does not divide the night into fixed ninety-minute blocks: sleep stages vary through the night, and a clock calculation cannot locate your next REM period.
Example: waking at 07:00
For a 07:00 wake time and eight hours of sleep, the intended sleep start is 23:00 on the previous day. Allowing twenty minutes to fall asleep gives a 22:40 bedtime. Adding a thirty-minute wind-down moves the start of preparation to 22:10.
What a bedtime plan cannot predict
- Falling asleep can take a different amount of time each night. The plan does not include time spent awake after initially falling asleep.
- Times use a simple local clock. Daylight-saving changes, travel across time zones and shift-work adaptation need separate planning.
- This is a scheduling aid, not an insomnia treatment or a sleep-restriction programme. Repeated difficulty sleeping needs more than an earlier time on a clock.
Common questions
Does wind-down count towards my sleep target?
No. It is preparation time before bedtime. The allowance for falling asleep is also separate from the hours you intend to spend asleep.
Why not calculate ninety-minute sleep cycles?
Cycles are not fixed ninety-minute appointments. This tool plans enough time for your chosen sleep duration instead of claiming to predict sleep stages.
Can I calculate wake-up time from bedtime?
Yes. Switch to wake-up time and enter your planned bedtime. The tool adds your allowance for falling asleep and your sleep target. Wind-down still starts before bedtime.