Free sleep tools
Free sleep calculators
Work out a bedtime from your alarm, add up the sleep you missed over the last seven nights, or find out whether you are a lark or an owl. Plain arithmetic, explained on the page.
Free · No account · Runs in your browser
Sleep Calculator
Enter your alarm time and get bedtimes in 90-minute blocks, or start from now and get wake-up times.
Open the toolSleep Debt Calculator
Enter the hours you slept over the last seven nights and compare them with your own target.
Open the toolChronotype Test
Enter when you sleep on workdays and free days and find out whether you are a morning lark or a night owl.
Open the tool
Ready when you are
Choose your next wake-up mission.
Download on the App StoreiPhone · iOS 26+ · Subscription and trial terms in the App Store