Tell it when you last ate, pick your protocol, and it shows you exactly when your fast ends and when your eating window closes.
Your fasting window
Fast started
8:00 PM
Fast ends — eat from here
12:00 PM
Eating window closes
8:00 PM
Fast for 16 hours, eat within a 8-hour window.
12:12
Fast 12 hours, eat for 12. A gentle starting point — suits almost everyone.
14:10
Fast 14 hours, eat for 10. A popular step up that fits a normal schedule.
16:8
Fast 16 hours, eat for 8. The most researched and widely used protocol.
18:6
Fast 18 hours, eat for 6. For those who want deeper metabolic benefits.
20:4
Fast 20 hours, eat for 4. An advanced approach — not for beginners.
OMAD
One meal a day — 23 hours fasting. Only for experienced fasters.
This calculator tells you when to fast today. FastSyncer tracks it for you every day, and starts a new fasting challenge on the first of each month. Free to download, free to join.
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