Sleep Calculator
Choose when you need to wake up or when you plan to go to bed. The calculator shows several sleep-time options using an approximate 90-minute cycle and 15 minutes to fall asleep.
Suggested times
—
Aim for enough total sleep first. Cycle timing is only an approximation.
How the Sleep Calculator Works
Sleep architecture changes through the night and cycle length is not exactly 90 minutes for everyone. This tool uses 90 minutes only as a planning shortcut and includes about 15 minutes for falling asleep.
Prioritise total sleep
For most adults, getting a consistent amount of sufficient sleep and keeping a regular schedule matters more than trying to wake at a mathematically perfect cycle boundary.
Health note: Persistent insomnia, loud snoring, breathing pauses, severe daytime sleepiness or other sleep problems deserve medical assessment. A calculator cannot diagnose a sleep disorder.