Sleep schedule
Wake-Up Time Calculator
If you already know when you will go to bed, this calculator suggests alarm times that line up with the end of a full sleep cycle. It adds the minutes you usually need to fall asleep, then counts forward in cycles of about 90 minutes. Waking near the end of a cycle, during lighter sleep, may feel easier than being woken from deep sleep.
How it works
Wake time = bedtime + minutes to fall asleep + (number of cycles x cycle length). Results wrap past midnight.
Example
Bed at 10:30 PM, 15 minutes to fall asleep, 90 minute cycles. Asleep at 10:45 PM. Six cycles (9 h) ends at 7:45 AM, five cycles (7.5 h) at 6:15 AM, four cycles (6 h) at 4:45 AM.
Assumptions and limits
- Cycle length is an average; real cycles vary between people and across the night.
- Brief awakenings during the night are normal and are not modeled.
- Adults generally need 7 or more hours, so the 4 cycle option is short for most people.
Frequently asked questions
Will waking at the end of a cycle stop grogginess?
It may help, but grogginess after waking (sleep inertia) also depends on how much sleep you got, your body clock and any sleep debt. Getting enough sleep on a regular schedule matters most.
How many cycles do adults need?
Most adults need at least 7 hours, which is roughly 5 cycles. Some people need more. Teens need 8 to 10 hours according to the CDC.
Does this work for naps?
For naps, a short nap of about 20 minutes, or one full cycle of about 90 minutes, are the common options. See the nap timing calculator.
Sources
Tools and screening scores are general information. They cannot diagnose or rule out a sleep disorder. Read our medical disclaimer.