Page updated
Changelog
What changed on Lull and when, newest first. Each correction says what the page said before.
Data updates also change the “last checked” dates on the methodology rows. Corrections are listed here with what was wrong.
: Clock-change rules, sunrise and jet lag data
- New data: the clock-change rules for the US, the UK, the EU, Canada (Ontario's Time Act) and south-east Australia, the American Academy of Sleep Medicine's daylight saving advice, NOAA's sunrise equations and the NHS advice on short trips, each with its own row on the methodology page. The sleep timing guides use them.
: A plain-text summary of the site for AI assistants
- New: llms.txt, a short plain-text list of every Lull calculator and trust page with one line on what each does, for AI assistants and search tools that read it.
: How we work, how we test, and clearer caffeine times
- New: an editorial and corrections policy and a how we test page, which lists the hand-worked test cases each calculator is checked against on every build. The about page was rewritten to say who runs Lull, how it is paid for and how to report an error.
- Changed: a caffeine cut-off more than 12 hours before bedtime now says when it falls, “the morning before bed”, “the afternoon before bed” or “the evening before bed”, and how many hours before bed it is; nearer cut-offs carry no label. A 4:30 AM bedtime used to show “By 4:35 AM this morning”, which could read as later than bedtime, and the words “after midnight” are gone. “Not today” now means only that no time in the 24 hours before bed works, the same for every bedtime: it used to depend on whether bedtime was before or after noon.
- The Lull Android app is now linked from the header, the phone menu and the footer of every page.
: Rebuilt the site as eight tools on one template
- All numbers now come from one data file, each value with a source, tier and the date we read it, listed on the new methodology and sources page.
- New: the night-shift sleep planner, split out of the jet lag planner, which now plans trips only.
- The sleep need by age tool now shows the US (CDC), UK (NHS), Canadian and Australian ranges side by side. The NHS gives no age bands for children, so the UK column says so.
- The sleep calculator no longer has a nap mode; naps have their own nap planner. The "sleep cycles explained" page was folded into the sleep calculator and the methodology page, and the melatonin page was retired; both addresses now redirect.
- Caffeine: the half-life choices are now NIOSH's 5 and 6 hours (they were 3, 5 and 8 hours; we could not re-read a source for the shortest and longest), and the drink amounts are now read from USDA FoodData Central records.
- Changed: the nap page said grogginess after a nap clears in 15 to 30 minutes. NIOSH's nap-duration page supports that for a nap of 20 or about 90 minutes, so it was not wrong for those naps. The page now gives both NIOSH figures: 15 to 30 minutes after those naps, and 30 to 60 minutes typically, observed up to 2 hours, for sleep inertia in general.
- Corrected: a caffeine study we cite (Drake and colleagues, 2013) measured sleep at home, not in a lab as the page said.
- Caffeine: when the half-life gives a clock time, the calculator now never shows one later than 6 hours before bed (a studio rule built on that study, whose 6 hours were for 400 mg of caffeine); a drink already at or under your bedtime figure still shows any time, and when no time today keeps a drink under your figure it says so instead of printing a clock time.
- The sleep debt calculator now gives the total shortfall only, without a repayment schedule, and the social jet lag calculator gives the gap and its band without a weekly plan or an hours-lost estimate.
: Cookie settings on every page
- The advertising script, which also runs the cookie-choice message, is now loaded on every page, so "Privacy and cookie settings" works wherever it appears.
: Guides replaced by tools
- The caffeine cut-off, sleep debt, nap, jet lag, social jet lag and sleep by age calculators replaced the guide articles on the same topics; the old addresses redirect to the matching tool. Three general guides (sleep hygiene, insomnia basics, sleep trackers) were removed.
- Corrected: a cycle length of 90 to 110 minutes had been credited to NINDS, which does not say it. The pages now cite the NHLBI's 80 to 100 minutes, and NINDS only for the first REM sleep about 90 minutes after falling asleep.
: Page-not-found page
- Added a custom page for addresses that do not exist, with links back to the calculators.
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