What changed and when.

Methodology gets formulas; About rewritten

Every calculator on the methodology page now shows its formula above Sources, rendered as typeset math via KaTeX, with sources re-audited against the lib/ code. About page rewritten in a shorter first-person voice.

Methodology · About

Two new articles: 90-minute cycles and baby wake windows

Wake Windows by Age pairs with the Baby Sleep Calculator and covers the AAP and NSF age-based ranges. Why 90-Minute Cycles Matter pairs with the Bedtime Calculator and covers the Kleitman and Dement research plus individual cycle variation.

Wake Windows by Age · Why 90-Minute Cycles Matter

Methodology page, citation footers, and llms.txt shipped

Every calculator now carries a Built on attribution block, the methodology page consolidates every formula and its sources at one URL, and /llms.txt is published for AI search engines.

Methodology · llms.txt

Site-wide editorial review

All 18 calculators and 11 articles reviewed against the citation roster in lib/content/citations.ts. Disclaimer rolled out to every YMYL page.

Catalogue complete: 18 calculators live

Final stage-5 calculators landed: chronotype, melatonin timing, schedule fixer, alcohol and sleep, teen sleep, and sleep banking. Site now covers all four clusters.

Circadian tools hub

Sitemap and breadcrumbs structured for indexing

BreadcrumbList JSON-LD on every page; sitemap pulls article modified dates from git, calculator dates from a stage-bucketed map.

Beachhead and volume calculators live

Sleep cycle, bedtime, wake-up time, sleep debt, and caffeine cutoff went live, followed by nap and how much sleep do I need.

Idea: a sleep calculator hub with the math shown

Got serious about health and started focusing on sleep. Looked at the calculators that already existed and felt they could be improved — assumptions hidden, sources missing, math not always holding up. The seed for SleepTools.co: a portfolio site with formulas present, assumptions transparent, and sources cited.