What this is
Free Fasting Calculator is a free set of scheduling tools: calculators for every common fasting protocol, a reverse calculator, a life-aware schedule planner, a timer that tolerates human error, and local history. Everything runs in your browser. There is no account, no subscription, and no upsell: the entire product is the free product.
Editorial standards
- No fake precision. We do not claim that specific hours trigger specific biological processes, and we do not predict weight loss from fasting duration. Where research is uncertain, we say so.
- No invented authority. No fabricated experts, reviewer credentials, quotes, studies, or proprietary datasets appear on this site. If a claim can't be supported, we soften it or leave it out.
- Calculation, not recommendation. The tools compute schedule mathematics and factual relationships (sleep overlap, meal conflicts). They never rank protocols as medically better or worse.
- Non-judgmental by design. A 14-hour fast against a 16-hour target is recorded as data, not failure. Streaks are optional and off by default.
How it's built
One deterministic, unit-tested calculation engine powers every page: the same code computes a 16:8 window on the homepage, the protocol pages, the timer, and the planner, so results never disagree. The site is static, fast, and works the same on a phone in a kitchen as on a desktop at work. Your data model is deliberately boring: timestamps in your own browser.
Contact & corrections
Found an error (mathematical, factual, or editorial)? We treat corrections as contributions. Contact the site operator and the page will be reviewed and dated when revised.