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Intermittent Fasting Calculator

Plan your intermittent fasting schedule with 6 protocols (16:8, 18:6, 20:4, OMAD, 5:2, ADF), eating window visualization, and macro targets. Free, fast, and private — runs entirely in your browser.

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How to Use Intermittent Fasting Calculator

  1. 1Select your fasting protocol (16:8, 18:6, etc.).
  2. 2Set your preferred eating window start time.
  3. 3Enter your stats for calorie and macro calculations.
  4. 4View your daily schedule and nutrition targets.

Frequently Asked Questions

Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating. Popular methods include 16:8, 18:6, and OMAD.

16:8 is the most popular starting point — fast for 16 hours and eat during an 8-hour window. It's sustainable and easy to follow.

Yes, completely free with no sign-up required. All calculations run in your browser.

Yes, the calculator provides calorie targets and macro breakdowns based on your goals (fat loss, maintenance, or muscle gain).

Using the Intermittent Fasting Calculator is simple: visit the tool page, enter your data or input into the provided fields, and get instant results. No downloads, installations, or sign-ups are required. The tool runs directly in your web browser for maximum convenience.

Yes, after running your calculation you can copy the results to your clipboard or take a screenshot. The Intermittent Fasting Calculator displays a detailed breakdown so you can easily record or share your numbers. No account is required to use or save results.

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About Intermittent Fasting Calculator

Plan your intermittent fasting schedule with 6 protocols (16:8, 18:6, 20:4, OMAD, 5:2, ADF), eating window visualization, and macro targets. Free, fast, and private — runs entirely in your browser.

NexTool's Intermittent Fasting Calculator is completely free to use with no sign-up required. Your data is processed directly in your browser and never sent to our servers, ensuring complete privacy and instant results.

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:(12:00 PM)
Your Daily Schedule
16h Fast
8h Eat
Fasting Window
8:00 PM - 12:00 PM
16 hours
Eating Window
12:00 PM - 8:00 PM
8 hours
What You Can Have During Fasting
✓
Water
Plain, sparkling, or with lemon
✓
Black Coffee
No sugar, cream, or milk
✓
Plain Tea
Green, black, or herbal (unsweetened)
✓
Apple Cider Vinegar
1-2 tbsp diluted in water
✓
Bone Broth
Light broth for electrolytes (may break strict fast)
✗
Anything with Calories
Juice, milk, sweeteners break your fast
Hydration Reminder
Aim for at least 2-3 liters (8-12 glasses) of water per day during intermittent fasting. Staying hydrated helps manage hunger, supports metabolism, and prevents headaches. Increase intake on active or hot days.
Enter your weight, height, and age above to calculate your personalized intermittent fasting plan.
Disclaimer

This calculator provides estimates based on the Mifflin-St Jeor equation and standard activity multipliers. Individual results may vary significantly based on metabolism, genetics, body composition, and adherence.

This is not medical advice. Intermittent fasting is not suitable for everyone, including pregnant or breastfeeding women, children, people with eating disorders, type 1 diabetes, or those on certain medications. Always consult a healthcare professional before starting any fasting regimen.