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Intermittent Fasting Calculator
Calculate your eating and fasting windows for 16:8, 18:6, 5:2, and other IF protocols with a benefits timeline.
Calculator
Intermittent Fasting Calculator
Calculate your eating and fasting windows for popular IF protocols.
Select Fasting Protocol
Most popular. 16 hours fasting, 8-hour eating window.
Last Meal Time
Your Schedule
Fasting Starts
08:00 PM
Eating Opens
12:00 PM
Eating Closes
08:00 PM
Fasting Tracker
1.6h into fast10%14.4h remaining
Calorie Suggestion
≈ 250 cal/hour during your 8h eating window
Benefits Timeline
12h
Glycogen Depletion
Body begins shifting from glucose to fat for energy.
16h
Fat Burning
Significant increase in fat oxidation and ketone production.
18h
Autophagy Begins
Cells start recycling damaged components — cellular cleanup.
24h
Deep Autophagy
Enhanced cellular repair and reduced inflammation.
48h
Growth Hormone Surge
Growth hormone levels can increase up to 5x baseline.