Plan what time to go to bed
Enter the time you need to wake up and compare suggested bedtimes for different amounts of sleep.
Sleep Calculator
About Sleep Cycles
A complete sleep cycle lasts about 90 minutes. It typically takes 15 minutes to fall asleep. Waking up between cycles helps you feel more refreshed. Most adults need 4-6 cycles (6-9 hours) per night.
7 AM
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Enter a time and click Calculate to see recommended bed times
Sleep Calculator
A sleep calculator helps you determine the optimal bedtime or wake-up time based on sleep cycles. Each sleep cycle lasts approximately 90 minutes, and waking up between cycles helps you feel more refreshed and energized. Use this tool to plan your sleep schedule and wake up feeling your best. Our Sleep Calculator takes the guesswork out of sleep scheduling. Simply input when you want to wake up, and it will calculate the optimal times to fall asleep based on completing full sleep cycles. Alternatively, if you're going to bed now, it can tell you the best times to set your alarm.
The results are intended for general planning only. Sleep cycles and individual sleep needs vary, so the suggested times should not be treated as medical recommendations or exact predictions.
Ways to Use the Sleep Calculator
Estimate a wake-up time
Start with your planned bedtime and calculate possible wake-up times based on different sleep durations.
Compare sleep schedules
Review several possible bedtime and wake-up combinations to choose a schedule that fits your routine.
Plan sleep before work or school
Use a required morning wake-up time to estimate when you may want to start getting ready for bed.
Adjust your bedtime routine
Compare earlier and later sleep schedules when changing your routine, travel schedule, or daily commitments.
Check sleep duration quickly
Use the calculator to understand approximately how much sleep time fits between a bedtime and wake-up time.
Sleep Calculator Features
- Bedtime calculation
- Wake-up time calculation
- Multiple suggested sleep schedules
- Approximate sleep-cycle planning
- Optional sleep latency adjustment
- 12-hour and 24-hour time support
- Quick schedule comparison
- Responsive mobile layout
- Light and dark themes
- Browser-based calculation
- No installation required
- Useful for work schedules
- Useful for school schedules
- Useful for travel planning
- Useful for bedtime planning
- Useful for morning routines
How to Use the Sleep Calculator
- 1
Choose what you want to calculate
Select whether you want to calculate a bedtime from your wake-up time or a wake-up time from your bedtime.
- 2
Enter your time
Choose the bedtime or wake-up time you want to use as the starting point.
- 3
Adjust available options
Select any available settings such as time format or estimated time needed to fall asleep.
- 4
Calculate your sleep schedule
Run the calculator to generate suggested bedtime or wake-up options.
- 5
Compare the results
Review the suggested times and compare which option best fits your schedule.
- 6
Use the result as a planning guide
Choose a schedule that works for you while remembering that individual sleep needs and sleep-cycle lengths vary.
Free Online Sleep Calculator
Use the sleep calculator directly in your browser to estimate possible bedtime and wake-up schedules. No account or separate application is required.
What Time Should I Go to Bed?
Enter the time you need to wake up and compare suggested bedtimes. This can help when planning sleep before work, school, travel, appointments, or an early morning schedule.
What Time Should I Wake Up?
Start with the time you expect to go to bed and calculate possible wake-up times based on different approximate sleep durations.
Sleep Cycle Calculator
The calculator can use approximate sleep-cycle timing to generate possible sleep schedules. Actual sleep cycles vary between people and throughout the night, so these results are estimates rather than exact predictions.
Bedtime Calculator
Use a required wake-up time to work backward and compare several possible bedtimes. This can make it easier to organize an evening routine around your morning commitments.
Wake-Up Time Calculator
Enter a planned bedtime and compare possible wake-up times. This can be useful when deciding how long you want to sleep or when planning an alarm for the next morning.