Bedtime Calculator

Enter your wake-up time to find a bedtime that fits your sleep needs.

Go to bed atWake up at
Wake me up at
15 min

Clock format

Common Wake-Up Times

Choose when you need to wake up to see suggested bedtimes.

How to Use the Bedtime Calculator

If your wake-up time is fixed, start here. If your bedtime is fixed instead, use the Wake-Up Time Calculator to plan your alarm.

  1. Enter the time you need to wake up.
  2. Adjust how long you usually take to fall asleep.
  3. Calculate suggested bedtimes.
  4. Choose a bedtime that gives you enough sleep for your needs.

Work backward from your morning alarm

Set your alarm time and adjust the fall-asleep allowance. Compare the durations beside each result before choosing a bedtime. For a 7 AM alarm and a 15-minute allowance, 11:15 PM leaves an estimated 7 hours 45 minutes in bed and 7 hours 30 minutes asleep.

The 90-minute blocks are planning estimates, not measurements of your sleep stages. See the formula and limitations. If your bedtime is fixed, use the Wake-Up Time Calculator to find suggested wake-up times.

If you've been sleeping less than your target, use the Sleep Debt Calculator to estimate your shortfall over the past week.

Sources: CDC sleep-duration guidance and NHLBI sleep stages.

Editorial review by the Bedtime Calculator Editorial Team · . Review is editorial, not medical.

Quick answers

Bedtime calculator FAQ

What time should I go to bed?

Enter when you need to wake up. The calculator works backward and shows bedtime options, with the longest sleep duration first.

How much sleep do I need?

Most adults need at least seven hours, while children and teens generally need more. Check sleep needs by age before choosing a result.

Source: Sleep needs by age

How does the bedtime calculator work?

The tool subtracts approximate 90-minute blocks and your fall-asleep allowance from your alarm time. Results round up to the next five-minute mark.

Source: How 90-minute sleep cycles work

How accurate is a bedtime calculator?

The times are planning estimates. Sleep cycles are not always exactly 90 minutes, so getting enough sleep matters more than hitting a precise cycle.

Source: Calculator methodology

Bedtime Calculator benefits

  • Compare sleep durations

    Compare options by how much sleep they allow.

  • Adjust your timing

    Account for the time you usually take to fall asleep.

  • No account needed

    Calculate sleep times without creating an account.

Sleep planning guides

Learn more about sleep

Choose a sleep target, understand the estimates, and build a bedtime you can keep.

View all guides
A child, teenager, adult, and older adult resting in their own cozy sleep spaces.
3 min read

How Much Sleep Do You Need by Age?

Check recommended daily sleep by age, including naps, and turn the guidance into a realistic bedtime or sleep target.