How the Weight Loss Calculator Works
This calculator uses the principle that 1 kg of body fat contains approximately 7,700 calories (3,500 calories per pound). By dividing your total weight to lose by your chosen weekly rate, it calculates a realistic timeline and the daily calorie deficit required.
What Is a Safe Rate of Weight Loss?
Health authorities including the NHS, CDC, and WHO recommend losing 0.5–1 kg (1–2 lbs) per week. At this rate, your body loses primarily fat rather than muscle, your metabolism stays relatively stable, and the diet is far easier to maintain. Faster rates — more than 1 kg/week — require very low calorie intakes that are difficult to sustain and may lead to nutritional deficiencies.
Frequently Asked Questions
How fast should I aim to lose weight?
Most health authorities recommend losing 0.5–1 kg (1–2 lbs) per week. This pace preserves muscle mass, is sustainable long-term, and avoids the metabolic slowdown associated with crash dieting.
How many calories do I need to cut to lose 1 pound per week?
One pound of fat equals approximately 3,500 calories. To lose 1 lb per week you need a deficit of 500 calories per day, either through eating less, exercising more, or a combination of both.
Why does weight loss slow down over time?
As you lose weight your body requires fewer calories to function. Your TDEE decreases, so the same calorie deficit produces less weight loss over time. Recalculating your targets every 5–10 lbs lost helps keep progress on track.
This calculator provides estimates based on general caloric principles. Individual results vary based on metabolism, activity level, and body composition. Always consult a healthcare professional before beginning a weight loss programme.