Turns out, hitting the sack early is not the best way to ensure you wake up on time for work or feel more energised. The correct way? Using the sleep calculator.

A sleep calculator works out when to go to bed by measuring sleep cycles. We’ve listed the best times to fall asleep if you need to wake up at 6, 7 and 8am. But first, what are sleep cycles? Lasting about 90 minutes, a sleep cycle consists of five stages – four are non-rapid eye movement (NREM) sleep and one is rapid eye movement (REM) sleep.

We move from light sleep in Stage 1 to a very deep sleep in Stage 4. Waking up, or being woken up, when you are at Stage 4 of a sleep cycle, would result in grogginess. The fifth stage, REM sleep, is when most dreaming occurs. See next slide for best timings.

Waking up at 6am
Time to sleep: Best to do so at 8.46pm, 10.16pm, 11.46pm, or 1.16am

Waking up at 7am
Time to sleep: Best to do so at 9.46pm, 11.16pm, 12.46am or 2.16am

Waking up at 8am
Time to sleep: 10.46pm, 12.16am, 1.46am, 3.16am

(Note: The sleep calculator takes into consideration the 14 minutes (on average) that people take to fall asleep naturally. You should be in bed earlier, so you can fall asleep at these timings.) 

Have a specific time to get out of bed so you don’t miss the bus or train? Enter it into the sleep calculator. For example, if you need to wake up at 6.35am, the best timings are: 9.21pm, 10.51pm, 12.21am or 1.51am.