How the weight loss calculator works
We start with your maintenance calories, your total daily energy expenditure, from the Mifflin St Jeor equation and your activity level. Losing about 1 kg of body fat takes a deficit of roughly 7,700 kcal (about 3,500 kcal per pound), so a pace of 0.5 kg a week needs a daily deficit of about 550 kcal.
Most calculators stop there and assume the same deficit every week. But as you lose weight, your body needs fewer calories, so the same intake produces a smaller deficit over time. Our calculator recalculates your maintenance every week at your new weight, which gives a more honest goal date and shows you if progress would stall.
How fast should I lose weight?
Health agencies such as the CDC and NHS recommend about 0.5 to 1 kg (1 to 2 lb) a week. Losing faster usually means more muscle loss, more hunger and a higher chance of regaining weight. We also keep your intake at or above 1,200 kcal for women and 1,500 kcal for men, since going lower without medical supervision makes it hard to get enough nutrients.
| Pace | Daily deficit | Best for |
|---|---|---|
| 0.25 kg (0.5 lb) a week | About 275 kcal | The last few kilos, or a very comfortable pace |
| 0.5 kg (1 lb) a week | About 550 kcal | Most people, sustainable long term |
| 0.75 kg (1.5 lb) a week | About 825 kcal | Larger starting weights |
| 1 kg (2 lb) a week | About 1,100 kcal | Short phases with plenty to lose |
Tips that make it stick
- Eat plenty of protein and vegetables to stay full on fewer calories.
- Add strength training two or three times a week to protect muscle.
- Sleep seven to nine hours, since poor sleep increases hunger.
- Recalculate every 5 kg or so, or use the milestones above as check points.
Pick a healthy goal first with the ideal weight calculator, set your macros with the calorie calculator, or try a low carb approach with the keto calculator and meal plan.
Sources: Mifflin St Jeor equation (1990); CDC and NHS guidance on healthy weight loss; Hall KD et al. on dynamic energy balance, The Lancet 2011.
