Intermittent Fasting Calculator

Calculate your personal intermittent fasting plans and estimate daily calorie needs for weight loss or maintenance. Instant results for free.

Intermittent Fasting Calculator

Important Considerations

Who Should Be Cautious?

While intermittent fasting can be beneficial for many, certain groups should consult healthcare professionals before starting:

  • Pregnant or breastfeeding women
  • Individuals with a history of eating disorders
  • People with certain medical conditions
  • Those on specific medications

Tips for Success

Stay Hydrated

Maintain proper hydration during fasting periods by drinking plenty of water throughout the day.

Balanced Nutrition

Maintain a balanced, nutrient-dense diet during eating windows to ensure proper nourishment.

Listen to Your Body

Pay attention to your body's signals and adjust your fasting schedule as needed for optimal results.

Exercise Regularly

Combine fasting with regular exercise for enhanced health benefits and better results.

Stay Consistent

Be consistent with your fasting schedule and patient with your progress for the best long-term results.

What Makes Our Calculator Unique?

Considering All Necessary Factors

  • Age
  • Weight
  • Height
  • Gender
  • Activity Level
  • Primary Goal
  • Fasting Method

Flexible Fasting Options

  • 14:10 Method
  • 16:8 Method
  • 18:6 Method
  • 20:4 Method
  • OMAD (One Meal A Day)
  • Alternate Day Fasting
  • Weekly Fasting Protocols

Personalized Calculations

  • Precise Base Metabolic Rate (BMR) estimation
  • Accurate Total Daily Energy Expenditure (TDEE) tracking
  • Customized calorie recommendations

Comprehensive Insights

  • Detailed fasting schedule recommendations
  • Weight loss projections
  • Nutritional macro guidelines
  • Personalized calorie targets

How to Use the Intermittent Fasting Calculator

Enter Personal Information

  • Input your age
  • Select weight unit (lbs or kg)
  • Choose height measurement (imperial or metric)
  • Select your gender

Provide Activity Details

  • Choose your activity level
  • Select your primary goal (weight loss or maintenance)

Select Fasting Method

  • Browse through multiple fasting protocols
  • Choose the one that best fits your lifestyle and goals

Calculate and Review

  • Click the "Calculate" button
  • Review your personalized intermittent fasting plan

Frequently Asked Questions

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Basics of Fasting

What is intermittent fasting?
Intermittent fasting is a dietary method that cycles between periods of eating and fasting. Common schedules include 16/8 (16 hours of fasting and 8 hours of eating) and OMAD (One Meal a Day).
What does fasting do to your body?
Fasting triggers fat burning, improves insulin sensitivity, and reduces inflammation. It also helps in cellular repair and longevity by activating autophagy.
What is a fasting window calculator?
A fasting window calculator helps you calculate the fasting and eating times based on your chosen intermittent fasting schedule, such as 16/8 or 18/6.

Types of Fasting

What is OMAD fasting?
OMAD (One Meal a Day) fasting is a form of intermittent fasting where you fast for 23 hours and eat all your calories in a single meal within one hour.
What is dry fasting?
Dry fasting is a type of fasting where no food or liquids, including water, are consumed. This type of fasting is intense and should be done with caution.
What is dirty fasting?
Dirty fasting allows for low-calorie intake, like coffee with a bit of cream, during the fasting period.
How does the 16/8 intermittent fasting schedule work?
In the 16/8 method, you fast for 16 hours and eat within an 8-hour window. For example, you could eat between 12 PM and 8 PM and fast until 12 PM the next day.

Weight Loss and Benefits

How does intermittent fasting work for weight loss?
Intermittent fasting helps in weight loss by limiting eating times, reducing calorie intake, and boosting metabolism, which helps the body burn stored fat for energy.
What is the best intermittent fasting schedule for weight loss?
The 16/8 and 18/6 schedules are popular for weight loss, as they are easier to follow consistently and provide enough time for effective fat-burning.
How effective is intermittent fasting for weight loss?
Intermittent fasting is highly effective for weight loss as it limits eating times, helps control calorie intake, and improves metabolic rate, leading to sustainable fat loss.
Can intermittent fasting cause muscle loss?
Intermittent fasting, when combined with adequate protein intake and resistance training, generally preserves muscle mass and promotes fat loss instead.

Health Benefits and Risks

What are the benefits of intermittent fasting?
Benefits include weight loss, improved metabolism, better blood sugar control, reduced inflammation, and improved heart health by lowering cholesterol and blood pressure.
Can intermittent fasting lower cholesterol?
Yes, intermittent fasting can help lower LDL cholesterol and triglycerides, which improves heart health by reducing cardiovascular risk.
Is intermittent fasting bad for your heart?
No, intermittent fasting can benefit heart health by lowering cholesterol, blood pressure, and triglycerides, reducing the risk of heart disease.
What are the benefits of water fasting?
Water fasting helps with detoxification, reduces blood sugar and insulin levels, helps in fat burning, and enhances mental clarity.
What are the benefits of fasting for 48 hours?
Fasting for 48 hours improves insulin sensitivity, promotes fat burning, activates autophagy, and provides a mental reset, though it's best done occasionally under guidance.

Special Considerations

Is intermittent fasting safe for women over 40?
Intermittent fasting is generally safe for women over 40, but it's advisable to choose a gentler schedule, such as 12/12 or 14/10, to support hormonal balance.
Can intermittent fasting help with perimenopause symptoms?
Yes, intermittent fasting may help manage weight, reduce inflammation, and improve energy levels, which can support women during perimenopause.
Can intermittent fasting cause constipation?
Yes, some people may experience constipation with intermittent fasting, especially if they don't drink enough water or consume enough fiber during eating windows.
Is water allowed during intermittent fasting?
Yes, drinking water during intermittent fasting is essential for staying hydrated and supporting metabolism. Black coffee and unsweetened tea are also allowed.
How long should I water fast for health benefits?
A 24- to 72-hour water fast can provide significant health benefits, including improved insulin sensitivity, cellular repair, and increased fat burning. However, it's important to consult a doctor before extended fasting.

About Intermittent Fasting Calculator

The Intermittent Fasting Calculator is a free tool developed to calculate personalized fasting plans considering age, weight, height, gender, and activity level and estimate the daily caloric needs, basal metabolic rate (BMR), and total daily energy expenditure (TDEE).

You can choose a fasting goal—weight loss or maintenance—and select a fasting type, from the popular 16:8 to more intense schedules like OMAD, or even alternate-day fasting.

The calculator generates a structured fasting schedule, adjusted daily calorie targets, and potential weight loss over time.

Additionally, it also provides macronutrient guidance on protein, carbs, and healthy fats within the chosen eating window.

Common Intermittent Fasting Schedules

The best intermittent fasting schedule depends on your goals, lifestyle, and experience level. Here are some popular IF schedules:

Fasting Type Fasting Period Eating Window Suitable For
16/8 16 hours 8 hours Beginners, weight loss goals
18/6 18 hours 6 hours Intermediate fasters
20/4 20 hours 4 hours Experienced fasters
OMAD (One Meal A Day) 23 hours 1 hour Advanced, calorie restriction
Alternate Day 24 hours on/off Varies Advanced, intense fat loss

Benefits of the Intermittent Fasting Calculator

Using a fasting calculator has several advantages:

  • Personalized Scheduling: Tailors fasting hours based on your preferences.
  • Calorie Tracking: Helps maintain calorie targets within the eating window.
  • Weight Loss Projections: Estimates how much weight you can lose over time.
  • Nutrition Advice: Suggests daily protein, carbs, and fat intake for balanced nutrition.

Common Challenges of Intermittent Fasting

  • Hunger and Cravings: Adjusting to fasting periods can be difficult at first.
  • Low Energy: Low blood sugar levels may cause fatigue during the initial stages.
  • Hydration: Drinking water is crucial to stay hydrated and reduce hunger.

Comparing Fasting Types: Intermittent vs. Water Fasting

Aspect Intermittent Fasting Water Fasting
Duration Varies (16/8, 18/6, etc.) 24-72 hours
Consumption Water, black coffee, unsweetened tea Only water
Goal Weight loss, health benefits Detoxification, deep cellular repair
Suitable For All levels Intermediate to advanced fasters