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Intermittent Fasting Calculator – Plan Your Eating Window

Calculate fasting and eating windows for your IF schedule

For informational purposes only. Consult a healthcare provider before starting any fasting regimen.
Calculate Schedule

How to Use

  1. Select your intermittent fasting schedule
  2. Choose when you want to start eating
  3. Click calculate to see your eating and fasting windows
  4. Follow the schedule for your chosen fasting method

What is Intermittent Fasting?

Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating. Unlike traditional diets that focus on what you eat, IF focuses on when you eat. It doesn't specify which foods to eat but rather when you should eat them.

During fasting periods, you consume little to no calories. During eating windows, you can eat normally, though maintaining a balanced, nutritious diet is recommended for best results.

Popular Fasting Methods

MethodFasting PeriodEating WindowBest For
16:816 hours8 hoursBeginners, daily routine
18:618 hours6 hoursIntermediate fasters
20:4 (Warrior)20 hours4 hoursAdvanced fasters
OMAD23 hours1 hourExperienced fasters
14:1014 hours10 hoursGentle introduction
5:22 days restricted5 days normalWeekly flexibility

Potential Benefits of Intermittent Fasting

Research suggests several potential health benefits of intermittent fasting:

  • Weight loss and fat loss without calorie counting
  • Improved insulin sensitivity and blood sugar control
  • Enhanced cellular repair through autophagy
  • Reduced inflammation markers
  • May support heart health by improving cholesterol and blood pressure
  • Potential cognitive benefits and brain health
  • Simplified meal planning and reduced decision fatigue
  • May promote longevity based on animal studies

Getting Started with IF

Tips for starting intermittent fasting successfully:

  • Start with a gentle schedule like 14:10 or 16:8
  • Stay hydrated during fasting periods with water, black coffee, or tea
  • Ease into it gradually rather than jumping to extreme schedules
  • Plan your eating window around your lifestyle and schedule
  • Focus on nutrient-dense foods during eating windows
  • Listen to your body and adjust as needed
  • Be consistent for best results
  • Don't compensate by overeating during eating windows

Who Should Avoid Intermittent Fasting

Intermittent fasting is not suitable for everyone. Avoid IF or consult a doctor if you:

  • Are pregnant or breastfeeding
  • Have a history of eating disorders
  • Are underweight or have nutritional deficiencies
  • Have diabetes or blood sugar regulation issues (without medical supervision)
  • Take medications that require food
  • Are under 18 years old
  • Have a history of amenorrhea (missed periods)
  • Experience negative symptoms like extreme fatigue or dizziness

Frequently Asked Questions

What can I drink during fasting periods?
During fasting, you can drink water, black coffee, unsweetened tea, and other zero-calorie beverages. Avoid drinks with calories, sugar, or artificial sweeteners as they can break your fast.
Will I lose muscle on intermittent fasting?
When done properly with adequate protein intake and strength training, intermittent fasting typically preserves muscle mass. In fact, IF may help maintain muscle better than traditional calorie restriction by optimizing growth hormone levels.
Can I exercise while fasting?
Yes, many people exercise during fasting periods. Light to moderate exercise is generally fine. For intense workouts, some prefer exercising near the end of their fast or during their eating window. Listen to your body and adjust timing as needed.
How long does it take to see results?
Most people notice changes within 2-4 weeks of consistent intermittent fasting. Initial benefits like reduced bloating may appear within days, while weight loss and metabolic improvements typically become noticeable after 2-8 weeks.

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