Sleep Calculator
Use 90-minute sleep cycles plus a typical 14-minute fall-asleep buffer to find recommended bedtimes or wake-up times.
Recommended times
Sleep duration
About sleep cycles
A complete sleep cycle lasts approximately 90 minutes and consists of light sleep, deep sleep, and REM stages. Most adults complete 4–6 cycles per night. Waking at the end of a cycle is generally less groggy than waking mid-cycle.
The US National Sleep Foundation publishes a recommended range of 7–9 hours for adults aged 18–64. Times shown are reference targets — individual sleep needs vary.
Explore more
Also try:
Days Until calculator ·
Hours ↔ minutes.