Intermittent Fasting Calculator
Track your fasting windows, calculate eating periods, and monitor your intermittent fasting progress.
Important Health Disclaimer
This calculator provides general health information based on standard medical formulas and WHO guidelines. Results are for informational and educational purposes only and should not be considered as professional medical advice, diagnosis, or treatment recommendations.
For health concerns, medical conditions, fitness plans, or dietary decisions, please consult with qualified healthcare professionals, licensed physicians, registered dietitians, or certified fitness trainers who can evaluate your individual health status and medical history.
Individual health needs vary significantly. These calculations are general estimates and may not be appropriate for everyone, especially those with existing medical conditions, pregnant women, children, or elderly individuals.
Not a substitute for professional medical advice
Fasting Settings
Current Zone
Fat Burning
12.0 hours fasted
4.0 hours until eating window (12:00)
During Your Fast
- • Water, black coffee, and plain tea are OK
- • Avoid any calories to maintain fast
- • Stay hydrated - aim for 8+ glasses of water
- • Light activity is fine, avoid intense exercise
Fasting Zones Timeline
| Hours | Zone | What Happens |
|---|---|---|
| 0-4h | Fed State | Body digests and absorbs food, insulin rises |
| 4-12h | Early Fasting | Insulin drops, body starts using stored glucose |
| 12-18h | Fat Burning | Glycogen depletes, body switches to burning fat |
| 18-24h | Ketosis | Ketone production increases, enhanced fat burning |
| 24h+ | Autophagy | Cellular cleanup and regeneration begins |
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