What time should I go to bed so I don’t wake up tired? Use our sleep calculator to find out

Let our expert tool put an end to confusion over sleep cycles and bedtimes

A recent study found that consistent bedtimes can decrease the risk of an early death by almost a third. 
As the clocks go back an hour early on Sunday — affecting the nation’s health as well as canine anxiety levels — there is renewed focus on the importance of getting enough shut-eye. 
But what time should you go to bed to make sure you sleep well throughout the night?  Enter the time you’d like to wake up in our tool below and, based on 90-minute sleep cycles, we can tell you the best times to go to bed to wake up feeling fresh. 
We’re used to hearing that we need eight hours of sleep a night to get the best out of our brains, with some of us – “short sleepers” – lucky enough to do well on just five or six. Other people – “long sleepers” – find it hard to get through the day with less than nine hours of sleep. 
Worse than a lack of sleep then could be disruption to our sleep-wake cycles as they’re halfway done, not least because all of these different stages come with different benefits for our health. 
It’s the first half of our night’s rest that seems to be key says Prof David Ray, professor of endocrinology at the University of Oxford, as that time is often when the body completes its “vital repair processes”. Disruption to these can leave us feeling exhausted, and we all know that “if we have a bad night’s sleep then we end up feeling dreadful”, regardless of when we actually go to bed. 
Keeping a consistent bedtime is one of the best ways to get high-quality rest every night, says Charalambos Kyriacou, president of the European Biological Rhythms Society and a professor at the University of Leicester. 
“People are programmed to have different chronotypes that dictate how much sleep they need and whether they’re early birds or night owls,” Prof Kyriacou says. 
“You can be genetically coded to want to get up early or late, but if you don’t want to have your sleep disrupted and wake up feeling tired, then it’s best to have a consistent bedtime.” 
This in large part is because our brains move us through a number of different sleep “phases” as we go through the night, lasting around ninety minutes each. 
“When you first fall asleep you’re sleeping lightly, for only a short spell,” says Prof Ray. “Then you’ll move into a more prolonged state of deep sleep, and then slow wave sleep, which seems to be especially important for restorative sleep. After this comes REM sleep, where you dream, and this period seems to be key to things like memory formation and creativity,” Prof Ray adds. 
So to wake up feeling refreshed, it may prove best to time your wake-ups around the likely start and end of your sleep cycles. Our calculator is designed to help you work out a regular bedtime that will allow you to wake up each morning feeling fresh. 
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