What Time Should I Go to Bed? A Simple Way to Work It Out
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If you have to be up at 6am, what time should you go to bed? Online sleep calculators give a precise answer down to the minute, based on 90-minute sleep cycles. The real answer is simpler and a bit less exact. This guide covers how to work out what time to go to bed, and why the calculators aren't as scientific as they look.
The short answer: count back 7 to 9 hours from your wake-up time, then add about 15 minutes to fall asleep. For a 6am wake-up, that means lights out between about 8:45pm and 10:45pm. Start in the middle, keep the same times every day, and adjust based on how you feel.
Bedtime by wake-up time
This table counts back 7 to 9 hours of sleep, plus 15 minutes to fall asleep.
| Wake-up time | Go to bed between |
|---|---|
| 4:00am | 6:45pm and 8:45pm |
| 5:00am | 7:45pm and 9:45pm |
| 6:00am | 8:45pm and 10:45pm |
| 7:00am | 9:45pm and 11:45pm |
| 8:00am | 10:45pm and 12:45am |
Most adults need between 7 and 9 hours. Teenagers need 8 to 10, so their bedtime should be about an hour earlier. See how much sleep do I need?
Do sleep calculators work?
Sleep calculators assume that sleep runs in exact 90-minute cycles, and that waking at the end of a cycle leaves you feeling fresh. So they tell you to go to bed at, say, 9:46pm or 11:16pm.
Sleep does run in cycles. healthdirect says your sleep is divided into cycles that last for about 90 minutes (source). But the timing isn't exact enough to plan around:
- Cycle length varies. The Sleep Health Foundation says the variation may be from around 60 to 110 minutes, with unpredictable differences in the same person from night to night.
- Time to fall asleep varies. A typical figure is 10 to 20 minutes, but the same person can take quite different times on different nights.
- Nobody can predict where you'll be in a cycle seven hours from now.
The Sleep Health Foundation's view is blunt: the assumptions sleep calculators make, and the advice they give, are not based on scientific evidence (source).
What matters more than the exact minute
- Enough sleep. Getting 7 to 9 hours matters more than which minute you wake. If you're short on sleep, you're more likely to wake up groggy whatever time the alarm goes.
- Regular times. The Sleep Health Foundation's advice is to give your body clock routine sleep and wake times. A steady 10:30pm bedtime beats a calculated one that changes every night.
- Feeling sleepy. Going to bed too early can also disturb your sleep. If you're lying awake for an hour, your bedtime is too early.
- Not too long in bed. healthdirect suggests limiting your time in bed to no more than 8 hours.
How to find your own bedtime
- Fix your wake-up time first. Work or school usually decides this.
- Count back 8 hours and 15 minutes. That's your starting bedtime.
- Keep it for a week, including the weekend.
- Check how you feel. If you fall asleep within about 20 minutes and feel fine during the day, it's working.
- Adjust by 15 minutes. Still tired? Go to bed earlier. Lying awake? Go later.
If your current bedtime is a long way from your target, move it gradually. See how to fix your sleep schedule.
Why you still wake up groggy sometimes
That heavy, foggy feeling after waking is called sleep inertia. It's more likely if you're woken suddenly from deep sleep, and it's worse when you're short on sleep. It usually passes within minutes, but it can last longer. Light, movement and getting straight out of bed all help. See why do I feel groggy after waking up?
Early starts
A 4am alarm means a bedtime around 7 or 8pm, when it's still light in summer and the rest of the house is awake. Blackout curtains, earplugs and a firm routine help. See how to wake up at 4am for work.
Where the Sovune Nudge fits
We make the Sovune Nudge, a vibrating alarm wristband, so we're not neutral. Once you've worked out your times:
- One fixed alarm, every day. It's set on the band, with no app or phone, so your wake-up time stays the same without a screen by the bed.
- A gentler start. It begins as a tap, with three intensity levels that build, rather than a sudden loud ringtone.
- A full minute of vibration, stepping up through the levels, felt on your wrist rather than heard across the room.
- Silent, so if you're up at 4 or 5am, the rest of the house keeps sleeping.
- Three separate alarms, for changing rosters.
It comes with a 30-day money-back guarantee.
Quick answers
What time should I go to bed if I wake up at 6am? Between about 8:45pm and 10:45pm, which gives you 7 to 9 hours of sleep plus time to fall asleep.
What time should I go to bed if I wake up at 5am? Between about 7:45pm and 9:45pm.
Are 90-minute sleep cycles real? Sleep does run in cycles of about 90 minutes, but the length varies from around 60 to 110 minutes, so you can't time your alarm to them reliably.
Is it better to get 7.5 hours than 8 hours of sleep? There's no good evidence that it is. Getting enough sleep at regular times matters more.
For every type of silent alarm compared, see our complete guide to vibrating alarms in Australia.