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Intermittent Fasting Timer

Track your intermittent fasting cycles with a live countdown timer. Supports 16:8, 18:6, 20:4, and OMAD protocols. Saves progress to localStorage with fasting history and stats.

Health

Fasting Mode

Ready to start your Fast 16h, Eat 8h fast?

Your Fasting Stats

Completed

fasts

Total Hours

fasted

Longest Fast

hours

About These Fasting Protocols

16:8 — Fast 16h, Eat 8h

The most popular and beginner-friendly protocol. Fast for 16 hours and eat all your meals within an 8-hour window. A common approach is skipping breakfast and eating between 12 PM and 8 PM.

18:6 — Fast 18h, Eat 6h

A moderate protocol that extends the fasting window to 18 hours with a 6-hour eating window. Often chosen by those who have adapted to 16:8 and want more fasting time for deeper ketosis.

20:4 — Fast 20h, Eat 4h

A more advanced protocol with a 4-hour eating window (often called the Warrior Diet). Typically involves one large meal and a small snack within the window.

OMAD — One Meal A Day

One Meal A Day — the most intense standard protocol. Eat all your daily calories in a single meal within a 1-hour window. Requires significant adaptation and nutrient-dense eating to meet nutritional needs.

Frequently Asked Questions

What can I consume while fasting?▾

Water, black coffee, and unsweetened tea are generally considered acceptable during fasting windows. Some people also allow bone broth or apple cider vinegar. Anything with significant calories (above ~10-15 kcal) will break the fasted state.

How long does it take to adapt to intermittent fasting?▾

Most people adapt to 16:8 within 1-2 weeks. During the adaptation period, you may experience hunger, irritability, and lower energy. Staying hydrated and keeping busy during the fasting window helps. Start with 12:12 and gradually increase the fasting window.

Will I lose muscle while fasting?▾

Research shows that intermittent fasting preserves muscle mass as effectively as traditional calorie restriction when protein intake is adequate (1.6-2.2g per kg of body weight). Strength training during the eating window further protects muscle.

Can I exercise while fasting?▾

Yes. Many people perform well training in a fasted state, especially for low-to-moderate intensity cardio. High-intensity or heavy strength training is typically better performed during or near the eating window for optimal performance and recovery.

Is intermittent fasting safe for everyone?▾

Intermittent fasting is safe for most healthy adults, but not recommended for pregnant or breastfeeding women, individuals with a history of eating disorders, people with diabetes on medication, or those who are underweight. Consult a healthcare professional before starting any fasting regimen.

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How to Use This Tool

Select your preferred fasting protocol: 16:8, 18:6, 20:4, or OMAD.
Click the 'Start Fast' button to begin tracking your fast.
Watch the live countdown timer track your remaining fasting time.
When the fasting window ends, the eating window timer starts automatically.
View your fasting history including completed fasts, total hours, and longest fast.
Use the 'End Fast' button to manually stop your current cycle.

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