Intermittent Fasting Calorie Calculator
Determine your daily calorie budget and eating window meal targets for 16:8, 18:6, 20:4, and OMAD (One Meal A Day) intermittent fasting protocols.
🏃 Interactive Intermittent Fasting Calorie Calculator
About this Calculator
Methodology & Formulas: This Intermittent Fasting calculator uses standard physiological formulas and evidence-based guidelines to provide accurate estimates.
Reviewed by: Dr. Rekha Kumar, M.D., M.S., Lead Medical Reviewer
Last Updated: August 2026
Sources & Citations: Guidelines from the NIH and CDC were consulted in the creation of this tool.
Disclaimer: This tool is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider.
Frequently Asked Questions
Do calories still matter during intermittent fasting?
Yes. Fasting creates a time-restricted eating window, but fat loss still requires an overall daily calorie deficit.
How many calories should I eat during a 16:8 eating window?
Divide your daily calorie deficit target (e.g. 1,600 kcal) across 2 or 3 balanced meals during your 8-hour window.
Does drinking black coffee break a fast?
Plain black coffee, green tea, and water contain 0–5 calories and will not break autophagic or metabolic fasting states.
Scientific References & Clinical Guidelines
- CDC Healthy Weight Guidelines - Centers for Disease Control and Prevention
- NIH National Heart, Lung, and Blood Institute (NHLBI) Obesity Guidelines
- PubMed studies on rate of fat mass vs. lean mass loss