Weight Loss Calculator
Frequently Asked Questions
How many calories equal one kilogram of fat?
One kilogram of body fat stores approximately 7,700 calories. To lose 1 kg, you need to create a total calorie deficit of 7,700 calories. At a daily deficit of 500 calories, that takes roughly 15–16 days. This is the core formula used by dietitians and this calculator.
What is a safe calorie deficit for weight loss?
A deficit of 500 calories per day is widely considered the safest and most sustainable level, resulting in roughly 0.5 kg (1 lb) of fat loss per week. Deficits above 1,000 calories per day risk muscle loss, nutritional deficiencies, and metabolic slowdown, especially without medical supervision.
Why does my weight loss slow down over time?
As your body gets lighter, your basal metabolic rate decreases — you burn fewer calories just existing. This is called metabolic adaptation. To continue losing at the same rate, you must periodically recalculate your TDEE and adjust your calorie target downward or increase physical activity to maintain the deficit.
Can I lose weight faster by exercising more?
Yes, exercise increases your total daily calorie expenditure, allowing a larger deficit without cutting food intake further. Strength training is especially valuable because it builds muscle, which raises your resting metabolism. Combining a moderate calorie deficit with regular exercise is the most effective long-term strategy.
Is the weight loss timeline from the calculator guaranteed?
No — it is an evidence-based estimate, not a guarantee. Real-world results vary due to water retention, hormonal shifts, metabolic adaptation, and tracking accuracy. Use the projection as a realistic target, plan for 10–15% extra time, and track weekly averages rather than daily scale readings for the clearest picture.
Recommended
Related Tools
Calorie Burned Calculator
Calculate calories burned during 50+ exercises and activities.
Calorie Deficit Calculator
BMI Calculator
Calculate your BMI from height and weight and get a detailed health report with BMI category, healthy weight range, body fat estimate, calories, macros and more.
Body Fat Calculator
Estimate body fat percentage using measurements like waist, neck, and height (Navy method).
TDEE Calculator
Calculate your Total Daily Energy Expenditure and daily calorie target for your fitness goal.