Intermittent Fasting Calculator (16:8, 18:6, 20:4 Schedules) | Rocking Tools

Plan your eating and fasting intervals for 16:8, 18:6, 20:4, and OMAD (One Meal a Day) intermittent fasting protocols.

BMR
1,659 kcal
Calories at total rest
Maintenance (TDEE)
2,571 kcal
Calories to stay the same weight
Your target
2,571 kcal/day
Adjusted for your goal
SUGGESTED DAILY MACROS
Protein20%
126g
Fat25%
71g
Carbs55%
356g

Estimates only โ€” individual metabolism varies. Consult a doctor or registered dietitian before making major dietary changes.

Today's Food Log

Search foods, select unit (grams, slices, pieces, cups, oz...), and track your daily macros.

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โš•๏ธMEDICAL & YMYL DISCLAIMERReviewed August 2026

Educational Purpose Only: The calculations, formulas, and estimates provided by this calorie & nutrition calculator are intended solely for educational, research, and informational purposes. They do not constitute medical advice, diagnosis, or personalized treatment plans.

Always consult a qualified healthcare professional, physician, or registered dietitian before making changes to your diet, exercise regimen, calorie intake, or pregnancy care plan. Never disregard or delay professional medical advice because of something you read on this website.

SCIENTIFIC FORMULA & METHODOLOGY
Time-Restricted Feeding (TRF) Windows
16:8 Protocol: 16 Hours Fasting / 8 Hours Eating Window
18:6 Protocol: 18 Hours Fasting / 6 Hours Eating Window
20:4 Protocol: 20 Hours Fasting / 4 Hours Eating Window

Time-restricted eating synchronizes food consumption with your circadian rhythm, optimizing insulin sensitivity and cellular autophagy.

Clinical Limitations & Considerations

Fasting is not recommended for pregnant women, individuals with a history of eating disorders, or type 1 diabetics without medical supervision.

Scientific References & Literature

  • de Cabo, R., & Mattson, M. P. (2019). "Effects of Intermittent Fasting on Health, Aging, and Disease." New England Journal of Medicine, 381(26), 2541-2551.

Frequently Asked Questions

What can you drink during the fasting window?

Water, black coffee, unsweetened green or herbal tea, and plain mineral water without zero-calorie sweeteners or milk.