Health & Fitness
Intermittent Fasting Calculator
Plan intermittent fasting windows and meals.
Formulas and edge cases are reviewed against authoritative references before publication. For methodology, editorial standards, or corrections, use the links below.
Frequently asked questions
Which IF protocol is best?
16:8 is most popular and sustainable. Start there and adjust based on results.
Can I drink during fasting?
Water, black coffee, and plain tea are fine. Anything with calories breaks the fast.
Will IF help me lose weight?
IF is a tool for calorie control, not magic. You still need a calorie deficit.
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About this tool
This Intermittent Fasting Calculator turns your inputs into practical results. Provide First Meal Time, Protocol, and Daily Calories to calculate Eating Window and Fasting Period.
Adjust values to compare scenarios and see how sensitive the result is. The calculation uses the numbers as entered, so double-check units and expect small differences from rounding in the displayed totals.