Track your intermittent fasting windows. Start your fast, stop when you eat — your history is saved automatically.
Not fasting
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Fasting Goal
16h fast → 8h eating window
0% of 16h goal
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Day streak
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Days logged
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Avg / day
Choose when you stopped eating and press Start Fast to begin tracking. Your history will appear here.
Back up your goal, history, and any active fast to move them to another browser or device. Importing a backup replaces the fasting data currently on this device.
Read the guide
How to Start Intermittent Fasting (16:8)
Learn the science, tips, and common mistakes — so every hour you fast counts.
Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating. The most popular approach is 16:8 — 16 hours fasting, 8 hours eating. It doesn't specify which foods to eat, just when.
Most people target 16 hours of fasting per day. After about 12–14 hours, your body begins to shift from burning glucose to burning stored fat. The last couple of hours are where many of the metabolic benefits are thought to occur.
Water, black coffee, and plain tea don't break a fast. They contain no calories and won't spike insulin. Avoid anything with milk, sugar, or sweeteners during your fasting window.
Your overnight sleep counts as part of your fast. If you finish eating at 8pm and sleep for 8 hours, you wake up having already fasted for 8 hours. You only need another 8 hours to hit the 16-hour target.
Missing a day or ending a fast early occasionally has minimal impact. What matters is averaging close to your goal over weeks and months. Don't let one short fast derail your routine.
Track your fasting windows with a persistent timer. Your fast continues even if you close the tab — just come back and stop it when you break your fast.
16:8 fasting
Start at 8pm, stop the next day at noon — 16 hours fasted
14:10 beginner
Start at 9pm, stop at 11am — a gentler 14-hour window
OMAD (one meal a day)
Fast for ~23 hours, eat within a 1-hour window
Intermittent fasting has been practised for thousands of years in religious contexts — Ramadan in Islam, Yom Kippur in Judaism, and Lent in Christianity all involve structured fasting periods. Modern research into its metabolic effects began gaining momentum in the early 2000s.
Start the timer after your last calorie-containing food or drink, using the convention you intend to follow consistently. Water and non-caloric drinks may fit some fasting plans, but rules differ. If fasting affects medication, pregnancy, diabetes, an eating disorder, or another health condition, ask a qualified healthcare professional before changing your routine.
Choose a window that fits your health, experience, sleep, work, and training rather than assuming a longer fast is automatically better. A goal is a planning aid, not a medical target. Start conservatively, stop if you feel unwell, and seek personalised advice when a health condition or medication could change what is safe.
History depends on the storage and account state shown by the page. Clearing browser data, using a private window, switching accounts, or losing connectivity during a sync can affect what is available on a device. Check the account and sync status before relying on the history, and keep a separate record when the timing is medically important.
No timer result should override symptoms or professional advice. Stop the fast and seek appropriate help if you feel faint, confused, severely weak, dehydrated, or otherwise unwell. People who are pregnant, under 18, managing diabetes, taking relevant medication, or living with an eating disorder should obtain qualified guidance before fasting.