Calorie Deficit Calculator for Weight Loss

Male Female

Sedentary (Office job, little exercise) Lightly Active (1-3 days/week) Moderately Active (3-5 days/week) Very Active (6-7 days/week) Extra Active (Physical job or 2x training)

Maintain Weight Mild Weight Loss (0.25 kg/week) Standard Weight Loss (0.5 kg/week) Extreme Weight Loss (1 kg/week)

What is a Calorie Deficit?

A calorie deficit occurs when you consume fewer calories than your body burns in a day. This state is the fundamental physiological requirement for weight loss. When your body doesn't get enough energy from food to sustain its activities, it begins to tap into stored energy—primarily body fat—to make up the difference.

How This Calculator Works

Our calorie deficit calculator uses the Mifflin-St Jeor Equation, widely considered the most accurate formula for predicting Basal Metabolic Rate (BMR). Here is the breakdown of the calculation process:

• BMR Calculation: This is the energy your body needs just to stay alive (breathing, heart rate, cell production) while at complete rest.
• TDEE Calculation: Your Total Daily Energy Expenditure is found by multiplying your BMR by an activity factor (from 1.2 to 1.9).
• Deficit Application: To lose 0.5kg (about 1lb) of fat per week, a daily deficit of approximately 500 calories is required.

Safe Weight Loss Practices

While it is tempting to aim for the "Extreme Weight Loss" setting, health experts generally recommend a gradual approach. Losing 0.5kg to 1kg per week is considered sustainable and safe for most individuals. Dropping your calorie intake too low (below 1,200 for women or 1,500 for men) can lead to muscle loss, nutrient deficiencies, and a slowed metabolism.

Key Factors Influencing Your Deficit

1. Protein Intake: High protein intake during a calorie deficit helps preserve lean muscle mass, ensuring the weight lost is primarily fat.

2. Strength Training: Lifting weights signals to your body that it needs to keep its muscle, encouraging it to burn fat stores for the deficit instead.

3. NEAT: Non-Exercise Activity Thermogenesis (like walking, fidgeting, or cleaning) can significantly increase your TDEE without the stress of a formal workout.

Example Calculation

Consider a 30-year-old male weighing 90kg at 180cm tall with a moderate activity level:

• BMR: ~1,880 calories.
• TDEE: ~2,914 calories (BMR x 1.55).
• Target for 0.5kg loss/week: 2,414 calories per day.

By consistently hitting this target, the individual creates a 3,500 calorie weekly gap, which is roughly equivalent to the energy stored in half a kilogram of body fat.