https://bedtime-math.pages.dev/Free sleep calculators: bedtimes for your alarm in 90-minute cycles, nap timing and recommended hours by age, with every number sourced.en-US https://bedtime-math.pages.dev/articles/shift-work-sleep-schedule/https://bedtime-math.pages.dev/articles/shift-work-sleep-schedule/Wed, 21 Oct 2026 12:00:00 GMTHow to plan sleep around night shifts using CDC/NIOSH guidance: sleep right after the shift, a dark room, pre-shift naps and a day-off compromise. https://bedtime-math.pages.dev/articles/caffeine-and-sleep-timing/https://bedtime-math.pages.dev/articles/caffeine-and-sleep-timing/Tue, 20 Oct 2026 12:00:00 GMTWhat the FDA, a sleep-lab study and the Sleep Foundation say about caffeine timing, turned into clock times for a 10:30 PM bedtime. https://bedtime-math.pages.dev/articles/how-long-should-a-nap-be/https://bedtime-math.pages.dev/articles/how-long-should-a-nap-be/Mon, 19 Oct 2026 12:00:00 GMTWhy 20 minutes and 90 minutes are the two nap lengths sleep experts point to, why about 45 minutes can backfire, and how to time the alarm. https://bedtime-math.pages.dev/articles/best-time-to-go-to-bed-6-630-7-am/https://bedtime-math.pages.dev/articles/best-time-to-go-to-bed-6-630-7-am/Sun, 18 Oct 2026 12:00:00 GMTBedtimes for 6:00, 6:30 and 7:00 AM alarms in 4, 5 and 6 sleep cycles, with a cycle-by-cycle timeline for each and the hours behind every option. https://bedtime-math.pages.dev/articles/90-minute-sleep-cycle-explained/https://bedtime-math.pages.dev/articles/90-minute-sleep-cycle-explained/Sat, 17 Oct 2026 12:00:00 GMTWhat a sleep cycle is, why 90 minutes is only an average, and how much a 10-minute difference in cycle length moves your ideal bedtime. https://bedtime-math.pages.dev/articles/how-much-sleep-do-you-need-by-age/https://bedtime-math.pages.dev/articles/how-much-sleep-do-you-need-by-age/Fri, 16 Oct 2026 12:00:00 GMTThe CDC table of recommended sleep by age, from newborns to adults 65+, with the source behind each row and the bedtime each range implies.