Macrition Macrition
Diet Patterns

Intermittent Fasting Calculator

Free intermittent fasting calculator plans your 16:8, 18:6, OMAD, or 5:2 schedule with fasted-hour tracking and eating window optimization.

Intermittent Fasting at a glance

Every number this page produces traces back to the reference values in the lead paragraph - the calculator adjusts WHO-table guidance by life stage, it never substitutes different source data. Rather than a fixed prescription, the Intermittent Fasting below personalizes it - the schedule is built from the fasting ratio you choose, and the calorie target comes from your own measurements.

Free intermittent fasting calculator plans your 16:8, 18:6, OMAD, or 5:2 schedule with fasted-hour tracking and eating window optimization. The page is written for people who fast by the clock: the eating window is set from your own schedule, and the diary tracks what lands inside the window, not just the daily total.

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Intermittent Fasting Calculator

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About Intermittent Fasting Calculator

Free intermittent fasting calculator plans your 16:8, 18:6, OMAD, or 5:2 schedule with fasted-hour tracking and eating window optimization.

This diet calculator helps you assess, plan, or optimize a specific dietary pattern. Diet quality is one of the strongest modifiable risk factors for chronic disease, research consistently shows that what you eat matters more than precise calorie counting for long-term health outcomes.

Evidence base

This calculator is based on validated dietary assessment tools and evidence from large cohort studies (Nurses' Health Study, EPIC, PREDIMED) and randomized controlled trials. Each dietary pattern has a unique evidence base for specific health outcomes.

Practical application

Use the result to identify areas for dietary improvement. Focus on one or two changes at a time rather than overhauling your entire diet. Sustainable changes produce better long-term results than dramatic overhauls that last only a few weeks.

Editorial and formula review
Formulas verified against published peer-reviewed sources Last verified

Formula sources, population limits, and references for this diet pattern calculator are documented in our public methodology. Read the methodology · Medical disclaimer

Frequently asked questions

Yes, it uses validated formulas and assessment tools from peer-reviewed research. Sources are cited in the article above.
Reassess every 4-8 weeks to track progress. Diet quality changes slowly, so more frequent assessment is not necessary.
The best diet is one you can sustain. Mediterranean, DASH, and low-carb all have strong evidence. Choose based on your preferences, health goals, and lifestyle.