Water Fasting Calculator
Plan your water fast duration and track your weight loss, calorie deficit, and hydration needs based on your body metrics.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Water Fasting Calculator
This calculator estimates your Basal Metabolic Rate (BMR), total calories burned during your fast, expected weight loss, and recommended water intake. All inputs must be in metric units (kg, cm, years).
- Enter your details: Fill in your current weight (kg), height (cm), age, and select your gender.
- Set fasting duration: Choose how many days you plan to fast (1–30 days).
- Select activity level: Pick the option that best matches your typical daily exercise.
- Click "Calculate": The results will appear below, showing:
- BMR – calories your body burns at rest per day.
- Total Calories Burned – estimated calories used over the fasting period.
- Estimated Weight Loss – based on ~7700 kcal per kg of fat.
- Water Intake Recommendation – total and daily water needed.
Note: This is an estimate only. Consult a healthcare professional before starting a water fast.
Previous Results
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Frequently Asked Questions
A water fast involves consuming only water for a set period, typically for health or religious reasons.
The estimate is based on average calorie deficit and assumes 7700 kcal per kg of fat. Actual results may vary.
Water fasting can be risky. Consult a healthcare professional before starting any extended fast.
