Free tools for night owls

By Kevin Buhl Jakobsen · Free, no account, nothing is saved

In the Journal we write about sleep, caffeine and living on unusual hours. The tools here make that advice concrete: put in your own times and see the answer straight away. Everything is worked out in your browser, so nothing you type is sent to us or saved. Under each tool we explain how it calculates, what it can't do, and which research the numbers come from.

Sleep calculatorThe best bedtime for your alarm, the best time to wake, and how long a nap should be. Caffeine calculatorHow much caffeine is still in your body at bedtime, and when your last cup should be. Social jetlagHow far your sleep shifts between the week and the weekend, and whether you are short of sleep. Night-shift plannerA plan for naps, light, caffeine and sleep from your shift times, and how to switch back.

The tools give general information and are not medical advice.