Sleep Calculator — free online bedtime tool
Ever wake up groggy even after a full night in bed, while a shorter sleep on another day left you fresh? A lot of it comes down to timing — waking up in the middle of a sleep cycle leaves you foggy. We added a free tool that figures out the good moments for you — Sleep Calculator — right in your browser.
What it does
Tell it when you want to wake up, and it shows the best bedtimes so you finish a full sleep cycle. Or tell it the time you're going to bed now, and it shows the best moments to set your alarm. It works out the times instantly, based on the natural rhythm of sleep cycles.
Nothing leaves your device
The whole thing runs in your browser. You don't sign in, nothing is uploaded, and nothing is saved anywhere. The times appear right on the page and disappear when you close it.
How to use it
- Open Sleep Calculator.
- Enter either your wake-up time or the time you plan to go to bed.
- Read off the suggested times and use the one that fits your morning.
It's free with no limit. There are more small tools on the Apps page.