What’s the Best Time to Go to Bed? Here’s What the Science Says

We know that we’re supposed to get eight hours of sleep every single night. But the real question is: which eight hours?

As in, when should we be sliding under the covers and settling into dreamland, and when should we be waking up? Technically, we could get eight hours of sleep in the middle of the day, but for most people that simply isn’t the healthiest or most efficient way of structuring their time.

So, when is the optimal time to go to bed?

There are two ways to look at it. One is to work out when you need to get up and reverse engineer it that way. Think about it. If you have to be out of bed every morning at 6am, then you know exactly when you need to be in bed. You probably need to be in bed by 9:40pm, winding down, so that you can drift into sleep by ten. (When we say winding down we mean reading a book or closing your eyes, not scrolling through Instagram and Facebook.) That way, you will have had your eight hours of sleep by six the following morning. And it’s easily adjusted to whatever waking time you’re working with.

But there’s another way of calculating when you need to go to sleep. A website called Hillarys Sleep Calculator suggests that instead of thinking in terms of hours, you need to think in terms of ‘cycles’.

Basically, everyone sleeps in units of cycles that all take about 90 minutes in total. During those cycles, your body moves through each stage and begins to heal, strengthen, and refresh your mind, body, and cells throughout the evening. Stage one is light sleep, moving incrementally through each stage until you get to stage four. This is the part of sleep that is hardest to wake from, and if you rouse from a stage four sleep you’re likely to feel groggy and unfocused. Stage five is when you do most of your REM dreaming. Over the course of an evening, you’re going to move through five or six cycles, and it takes about 14 minutes to fall asleep when you’re truly tired.

In order to feel fully rested, you need to wake up in between sleep cycles rather than in the middle of them. That means that you’ll feel less tired if you finish three sleep cycles (and only have four and a half hours of sleep, for example) than if you woke up in the middle of your fourth sleep cycle and disrupted the REM routine.

Using that logic, the Sleep Calculator has a handy way of working out when you should go to bed. All you need to do is input when you need to wake up the next morning and the website will crunch the numbers and return optimal timings of when to go to sleep.

For example, let’s go with that 6am wakeup call. You would think you need to go to bed at 10pm, right? Sleep Calculator has other ideas. Your options are 8:46pm for the most time in bed, 10:16pm to be well rested, 11:46pm at a pinch and there’s even the option of 1:16am if you’re having a night out.

All of these options could give you the rest that you need, and will allow you to wake up in the breaks between sleep cycles rather than in the middle of them.

Are there any other options though? Some studies – such as this one published by Stanford Medicine in 2024 – have found that those who go to sleep late have “higher rates of mental health disorders, including depression and anxiety”. (Gives a whole new meaning to ‘morning’ vs ‘night owl’ people, doesn’t it?).

Like with any routine, the key is picking a bedtime and sticking to it. If you have an irregular routine or, worse, no routine at all, you’re likely to see your concentration, focus and performance suffer.

But if you have a set bedtime and waking hour, and you stick to it, you will reap the rewards. You’re likely to have better sleep, be more alert and concentrated the following day, have more confidence and less anxiety, and will feel healthier, too.

Use the calculator, consult the studies or count backwards from your waking time the old-fashioned way. The most important thing is to pick a bedtime and stick to it. You’ll thank us later.