What the tools do
Our calculators add a selected fasting duration to a meal time and display the corresponding daily eating window. The live timer measures elapsed time. Nutrition estimates use the Mifflin–St Jeor equation and activity multipliers; they are estimates rather than a personal nutrition prescription.
No calculator can identify when autophagy begins in your body, diagnose ketosis, or determine whether fasting is appropriate for you. Longer fasting is not necessarily better.
FastingCalc Editorial
Articles are published under the FastingCalc Editorial name. This is a publication attribution, not the name of a clinician or a claim of medical credentials. The articles and calculators are not independently medically reviewed.
Editorial standards and corrections
- Sources are linked so readers can check the evidence. A linked study does not necessarily establish a benefit for every person or fasting schedule.
- Animal or laboratory findings should not be presented as established outcomes in humans.
- Dates indicate publication or editorial updates, not a clinical review.
- Reports of errors can be sent to aknexus.usa@gmail.com. Please include the page URL, the statement, and any supporting reference.
Privacy and funding
Calculator inputs are processed in your browser. The live timer saves its start time locally so it can resume. Optional analytics and any future advertising have separate data implications described in our Privacy Policy.
We are preparing the site for advertising through Google AdSense. Ads, if enabled, should be distinguishable from editorial content and do not constitute a medical endorsement.
Health information has limits
Discuss fasting with a qualified healthcare professional, particularly if you take medication or have a medical condition. Fasting is not suitable for everyone. Do not use a timer to delay care or continue fasting when unwell.
Read our medical disclaimer