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Calculators

• Sleep calculatorBedtimes and wake-up times that end on a whole sleep cycle.
• Sleep need by ageThe US, UK, Canadian and Australian ranges for any age, side by side, with a bedtime window.
• Night-shift sleep plannerA daytime sleep window, an optional nap before the next shift and a caffeine stop, with each NIOSH step quoted.
• Nap plannerOne alarm time for a nap, the length that fits your time, and the latest start before bedtime.
• Jet lag plannerNight-by-night bed and wake times when you cross time zones, with light times.
• Caffeine cut-off calculatorHow much caffeine is still active at bedtime, and the latest time for each drink.
• Sleep debt calculatorHours short of your need over your last 7 or 14 nights.
• Social jet lag calculatorThe gap between your workday and free-day mid-sleep, and your body clock's low point.
• All toolsThe hub, with what each tool answers.

Guides

• Sleep timing guidesEvery guide, by topic.
• Daylight saving time sleep plan: shift your bedtime before the clocks changeSmall bedtime steps, plus clock-change dates to 2028.
• Waking up when it’s still dark: a winter-morning planSunrise in 8 cities, a light plan and a checklist.
• 12-hour night shift sleep schedule: four worked examplesSleep, nap, caffeine and light times for each start.
• Jet lag east vs west: how many days to adjust, by time zones crossedOne table for 1 to 12 time zones, east or west.
• School-night bedtime chart by age and wake-up timeLatest lights-out for every school age, by wake-up time.
• Kids’ bedtime routine chart: printable and timed to your child’s bedtimeScreens off, tidy-up, teeth, book: timed to lights-out.
• Can you catch up on sleep on weekends? What the numbers sayWhat a lie-in pays back, and how far it moves your clock.
• A one-hour wind-down that fits your bedtimeFrom the last coffee to devices off, counted back from bed.
• How long does caffeine stay in your system? One cup, hour by hourWhat one coffee at 7 AM, noon, 3 or 5 PM leaves at bedtime.
• Sleeping on a plane: when to sleep, when to stay awake, and what to packNight where you land? Sleep. Day there? Stay awake.

Sources

• Methodology and sourcesEvery value behind the calculators, with its source, tier and the date we last read it.
• ChangelogDated changes and corrections.
• FAQQuestions about the site as a whole.

Site

• AboutWho runs Lull, how it is paid for, how the calculators are built and how to report an error.
• Editorial policyHow a figure gets onto the site, the three tiers, the quarterly source check and how corrections are logged.
• How we testEvery hand-worked case the calculators are checked against on each build.
• ContactHow to reach us and what to include.
• Privacy PolicyData, cookies, and advertising.
• Terms of ServiceTerms and the medical disclaimer.
• Lull app for AndroidThe Lull sleep calculator app: how it works, what it costs and how it compares with four other sleep apps.
• Lull Android app privacy policyData handling for the separate Lull Android app.