Sleep is imperative to how we operate each day. When we don’t get enough shut eye, it can leave us feeling lethargic and moody.
While medical experts recommend adults get seven to nine hours of sleep per night, sometimes you can still feel tired even when you are getting the right amount of sleep.
Luckily, there’s a sleep “calculator” that can help with this.
The way the calculator works is that it considers the sleep cycles, which last roughly around 90 minutes each and are a mix of light sleep, rapid eye movement (REM) sleep and deep sleep.
Ideally, humans should get through five to six sleep cycles a night.
Watch: How many hours should you sleep?
To use the calculator, made by curtain retailer Hillarys, simply enter the time you need to wake up the next morning and it will tell you when you should be hitting the hay.
For example, if you like to wake up at 7:30am, the calculator suggests you should head to bed at 10:16pm, 11:46pm, 1:16am or 2:46am to wake up feeling rested.
These timings take into account the fact that the average person takes around 14 minutes to fall asleep.
If all goes to plan, and you fall asleep within 14 minutes and wake up at the desired time, you should feel well rested.
According to the NHS, most adults need six to nine hours of sleep each day and lack of sleep has been linked to everything from diabetes to high blood pressure, heart disease and obesity.