Sleep Calculator

If you're one of those people who seems to feel absolutely knackered all the time, you're not alone. Trust us. 

There are plenty of factors that contribute towards getting a good night's sleep and allowing us to wake up feeling refreshed – but going to bed at the right time is arguably the biggest factor. 

While you might be thinking that the longer you spend in bed, the better night's sleep you'll get, it turns out there's actually a lot more to it than that. 

Fortunately, we can skip the complicated part, as startsleeping.org has done the hard work for us, by creating a sleep calculator which tells us exactly what time to go to bed, based on when we need to get up, in order to wake up with that wonderful sense of reinvigoration. 

Apparently, it's all to do with sleep cycles rather than getting more hours of sleep. If you wake up at the wrong time during a sleep cycle, you'll find yourself more tired – even if you were asleep for longer. Who knew? 

The Sleep Calculator factors in the average of 15 minutes it takes people to naturally fall asleep, so you don't necessarily need to be in bed by this time. 

A sleep cycle lasts about 90 minutes, during which time we move through five stages of sleep – 4 stages of non-rapid eye movement (NREM) sleep and one stage of rapid eye movement (REM) sleep. We move from light sleep in Stage 1 to a very deep sleep in Stage 4. It is difficult to wake someone in Stage 4 of a sleep cycle, which is why you might feel more groggy if you wake up during this stage. The fifth stage, REM sleep, is when most dreaming occurs. 

The Sleep Calculator website reads: "Getting a good night's sleep is about more than simply going to bed early – it's about waking up at the right time too. Using a formula based on the body's natural rhythms, the Sleep Calculator will work out the best time for you to rise or go to sleep". 

The calculator works on the principle that everyone sleeps in about five or six cycles which last roughly 90 minutes. 

For example, if you know getting out of bed at 6:35 is the optimum time so you can not miss the train and be punctual for work, enter it into the sleep calculator and you'll get a result. For a 06:35 AM rise time, go to bed at 09:21 PM, 10:51 PM, 12:21 AM or 01:51 AM. 

It means you can be very precise with your wake-up times and your bedtimes!