About SleepMath
SleepMath is the timing arithmetic: bedtimes and wake times that land on sleep-cycle boundaries, the debt a bad week accrues, and the caffeine curfew that protects the night.
SleepMath exists because sleep advice is either poetic ("prioritize rest!") or device-dependent. The cycle math — 90-minute stages, wake-back-to-bed timing, debt accounting — is public arithmetic that makes mornings measurably less awful.
Every calculator on SleepMath shows its formula and its assumptions on the page, so you can check the math, reproduce it in a spreadsheet, or argue with it. Inputs are processed entirely in your browser — nothing is sent to a server, and there are no accounts.
SleepMath is an independent, ad-supported project. We are not affiliated with any lender, brand, agency, or the sources we cite (NIH and CDC public guidance). If a number looks wrong, the contact page reaches a human who fixes it.
What makes SleepMath different
- Your numbers never leave your browser. Every calculator on SleepMath runs entirely on your device. We never see, store, or transmit the figures you enter — there are no accounts and no server-side processing of your inputs.
- Published methodology. Each calculator page explains the exact formula it uses and the assumptions behind it, so you can check our work or reproduce it in a spreadsheet.
- Free, forever, without a paywall. SleepMath is supported by advertising. There is no premium tier, no email gate, and no upsell.
Independence
SleepMath is an independent educational project. We are not affiliated with, endorsed by, or acting on behalf of any government agency, lender, insurer, or the organizations whose formulas and public data we reference (such as NIH and CDC public guidance). All trademarks and referenced standards belong to their respective owners.
Questions, corrections, or suggestions are genuinely welcome — get in touch.