Stop waking up groggy. Sleep Cycle Calculator finds the exact time you should go to sleep or wake up — based on your body's natural 90-minute sleep cycles.
Tell it when you need to wake up → get the best bedtimes
Going to sleep now → get the best wake-up times
Includes a nap calculator (20 / 60 / 90 min)
Free, no sign-up, no ads. Built because timing your sleep cycles actually works.
