A calorie deficit is the only requirement for weight loss: You need to consume less energy than your body burns. How large the deficit should be depends on your target weight, time frame, and daily expenditure.
In this article, you'll learn how to calculate your personal calorie deficit — safely, sustainably, and backed by science.
The 7,700 kcal Rule
One kilogram of body fat stores approximately 7,700 kcal of energy. To lose 1 kg, you need to save a total of 7,700 kcal — through eating less, moving more, or both.
Total deficit = Weight loss goal (kg) × 7,700 kcal
For example, if you want to lose 5 kg, you need a total deficit of 38,500 kcal. Over 12 weeks, that's a daily deficit of about 460 kcal.
Step 1: Calculate TDEE with the Mifflin-St Jeor Formula
Your TDEE (Total Daily Energy Expenditure) is your total daily calorie burn. It's based on your Basal Metabolic Rate (BMR), multiplied by an activity factor.
Men: BMR = 10 × Weight(kg) + 6.25 × Height(cm) − 5 × Age + 5
Women: BMR = 10 × Weight(kg) + 6.25 × Height(cm) − 5 × Age − 161
Learn more in our TDEE guide.
Step 2: Calculate Daily Deficit
Divide the total deficit by the number of days in your time frame:
Daily deficit = Total deficit ÷ Days
Your daily calorie target is then: TDEE − daily deficit.
Safe Deficit: What to Keep in Mind
- Never eat below 1,200 kcal/day — nutrient deficiencies and metabolic problems can occur.
- Lose a maximum of 0.5–1 kg per week — faster loss often leads to muscle loss and yo-yo effects.
- A moderate deficit of 300–500 kcal/day is ideal for most people.
Learn how to optimally split your calories into macronutrients in our macro guide.
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A calorie deficit is the key to weight loss. Calculate your daily calorie burn (TDEE), set a realistic goal, and use our Calorie Deficit Calculator for your personal daily target.
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