Weight Loss Calculator
A daily calorie target to reach a goal weight at a chosen rate, with the date you would get there.
Work out what you burn, decide how fast you want to lose, and this gives you the number to eat at and a realistic date. The safe rate for most people is a quarter to one kilogram a week — faster than that and an increasing share of what you lose is muscle.
How this is worked out
A kilogram of body fat stores roughly 7,700 kcal, so half a kilogram a week means an average daily deficit of about 550 kcal. The calculator refuses to take your target below about 1,200 kcal for women or 1,500 for men, because below those levels it becomes difficult to meet protein and micronutrient needs without supervision.
The timeline assumes a constant deficit, which is not what happens. As you get lighter your maintenance calories fall, so progress slows and most people need to recalculate every four to six kilograms. Weight also moves around by a kilogram or two day to day with water and food in transit — weigh weekly under the same conditions and watch the trend.
This calculator runs entirely in your browser. Nothing you enter is transmitted to us, saved on our servers, or shared with anyone.
Common questions
How fast can I safely lose weight?
About 0.5 to 1% of body weight a week suits most people. Very low calorie diets beyond that belong under medical supervision.
Why has my weight loss stalled?
Usually because maintenance calories have fallen as you got lighter, portions have quietly crept up, or water retention is masking fat loss. Recalculate, measure intake honestly for a fortnight, and keep protein and resistance training in place.