Sleep Calculator

Plan better bedtimes and wake-up times using 90-minute sleep cycles and average fall-asleep time. This free sleep calculator helps you work backward from a wake time or forward from a bedtime.

Calculate Sleep Times

Find recommended bedtimes based on 90-minute sleep cycles.
Find recommended wake-up times based on 90-minute sleep cycles.
Your result will appear here.

How the sleep calculator works

Sleep cycle timing:
The calculator uses repeated sleep cycles, usually around 90 minutes each.

Fall-asleep buffer:
It also adds time for falling asleep before the first cycle starts.

Wake-up planning:
Enter a wake time to see suggested bedtimes.

Bedtime planning:
Enter a bedtime to see suggested wake-up times.

Why sleep timing matters

Many people use sleep calculators to line up wake times with likely cycle endings. That can sometimes make waking up feel easier than waking in the middle of a cycle.

Good sleep habits, enough total sleep, and a consistent schedule are still the biggest factors.

What your result means

Your result shows several suggested times based on full sleep cycles. The calculator also highlights the common 5-cycle to 6-cycle range many people aim for.

This gives you a simple planning tool for bedtime and wake-up scheduling.

Sleep calculator tips

Frequently asked questions

How many hours of sleep do I need?

That varies by person, but many adults aim for around 7 to 9 hours each night.

What is a sleep cycle?

A sleep cycle is a repeating pattern of sleep stages. Sleep calculators often estimate each cycle at about 90 minutes.

Does waking between sleep cycles really help?

Some people feel better when waking near the end of a cycle, though it is not the only factor that affects sleep quality.

Why do I still feel tired even with a good sleep time?

Total sleep amount, sleep quality, stress, routine, and health factors can all affect how rested you feel.