From goal weight to a daily number
Most calorie calculators stop at maintenance. This one works backwards from your goal. It estimates your daily burn with the Mifflin–St Jeor formula and your activity level, then converts the weight change you want into a daily surplus or deficit over your timeframe.
The result is a single daily figure plus how fast that pace is as a share of your body weight, which is the quickest way to judge whether the plan is realistic.
Picking a timeline that works
If the calculator warns that your pace is too fast, extend the timeline rather than eating less. A longer plan with a modest deficit is easier to stick to and is more likely to keep the weight off.
Small deficits also protect your energy for training. Combine them with enough protein and some strength work to keep muscle while you lose fat.
When to get personal advice
If you have a medical condition, take medication, are pregnant or breastfeeding, are under 18 or have a history of disordered eating, speak to a doctor or registered dietitian before following any calorie target.
A worked example
A 30-year-old man who is 180 cm tall, weighs 80 kg and exercises three to five days a week burns about 2,759 kcal a day. To reach 75 kg in 10 weeks he needs to lose 0.5 kg a week, a daily deficit of 550 kcal, so his target is about 2,209 kcal. That pace is roughly 0.6% of his body weight a week, comfortably inside the usual guidance.
Questions people ask
How many calories should I eat to lose weight?
It depends on your size, age, sex, activity and how fast you want to lose. This calculator first estimates what you burn each day, then subtracts the daily deficit needed to reach your goal weight in the time you chose.
How is the daily deficit calculated?
Using the rule of thumb that about 7,700 kcal equals 1 kg of body weight (about 3,500 kcal per lb). The weight to lose is multiplied by 7,700 and divided across the days available. Actual results vary from person to person.
Why does it warn about my pace?
Losing more than about 1% of body weight a week, or eating very few calories, increases the risk of muscle loss, fatigue and nutrient gaps. When the plan is too aggressive the calculator says so, and the fix is to allow more weeks.
Does it work for gaining weight?
Yes. If your goal weight is higher than your current weight, the result is a daily surplus. Gaining slowly, around 0.25–0.5 kg a week, tends to add more muscle relative to fat.
Should I recalculate as I lose weight?
Yes. A lighter body burns fewer calories, so update your weight every few weeks and recheck the target.