Free sleep tools
Sleep calculators
Quick answers based on 90-minute sleep cycles. No sign-up, works on your phone.
Calculators
Bedtime calculator Enter the time you need to wake up and get the bedtimes that line up with 90-minute sleep cycles, so you wake between cycles instead of mid-cycle.Wake-up time calculator Going to bed now? Enter your bedtime and see which alarm times land at the end of a sleep cycle.Sleep cycle calculator How many full 90-minute sleep cycles fit in your night? Enter the hours you spend in bed.Nap calculator Enter when you lie down and get two alarm times: a 20-minute power nap or a full 90-minute cycle.If I go to sleep now, when should I wake up? Going to sleep right now? See the alarm times that land between sleep cycles, worked out from the current time.Sleep debt calculator Enter how much sleep you need and how much you got this week to see your sleep debt and how many nights it takes to repay.When should I stop drinking coffee? Enter your bedtime to find your caffeine cutoff. Based on caffeine's ~5-hour half-life and a sleep-lab study of coffee before bed.How much sleep do I need? Enter your age to see the recommended hours of sleep per night from the CDC, and the bedtime that fits a 7:00 AM alarm.How to start waking up earlier Enter your current and target wake times and get a day-by-day alarm plan that moves you 15 minutes every three days.
When to go to bed
What time should I go to bed to wake up at 5:00 AM? To wake up at 5:00 AM between sleep cycles, go to bed at 7:45 PM, 9:15 PM or 10:45 PM. Free bedtime calculator based on 90-minute cycles.What time should I go to bed to wake up at 5:30 AM? To wake up at 5:30 AM between sleep cycles, go to bed at 8:15 PM, 9:45 PM or 11:15 PM. Free bedtime calculator based on 90-minute cycles.What time should I go to bed to wake up at 6:00 AM? To wake up at 6:00 AM between sleep cycles, go to bed at 8:45 PM, 10:15 PM or 11:45 PM. Free bedtime calculator based on 90-minute cycles.What time should I go to bed to wake up at 6:30 AM? To wake up at 6:30 AM between sleep cycles, go to bed at 9:15 PM, 10:45 PM or 12:15 AM. Free bedtime calculator based on 90-minute cycles.What time should I go to bed to wake up at 7:00 AM? To wake up at 7:00 AM between sleep cycles, go to bed at 9:45 PM, 11:15 PM or 12:45 AM. Free bedtime calculator based on 90-minute cycles.What time should I go to bed to wake up at 7:30 AM? To wake up at 7:30 AM between sleep cycles, go to bed at 10:15 PM, 11:45 PM or 1:15 AM. Free bedtime calculator based on 90-minute cycles.What time should I go to bed to wake up at 8:00 AM? To wake up at 8:00 AM between sleep cycles, go to bed at 10:45 PM, 12:15 AM or 1:45 AM. Free bedtime calculator based on 90-minute cycles.
When to wake up
What time should I wake up if I go to sleep at 9:00 PM? Going to bed at 9:00 PM? Set your alarm for 4:45 AM or 6:15 AM to wake up between sleep cycles.What time should I wake up if I go to sleep at 10:00 PM? Going to bed at 10:00 PM? Set your alarm for 5:45 AM or 7:15 AM to wake up between sleep cycles.What time should I wake up if I go to sleep at 10:30 PM? Going to bed at 10:30 PM? Set your alarm for 6:15 AM or 7:45 AM to wake up between sleep cycles.What time should I wake up if I go to sleep at 11:00 PM? Going to bed at 11:00 PM? Set your alarm for 6:45 AM or 8:15 AM to wake up between sleep cycles.What time should I wake up if I go to sleep at 11:30 PM? Going to bed at 11:30 PM? Set your alarm for 7:15 AM or 8:45 AM to wake up between sleep cycles.What time should I wake up if I go to sleep at 12:00 AM? Going to bed at 12:00 AM? Set your alarm for 7:45 AM or 9:15 AM to wake up between sleep cycles.What time should I wake up if I go to sleep at 1:00 AM? Going to bed at 1:00 AM? Set your alarm for 8:45 AM or 10:15 AM to wake up between sleep cycles.