Calorie Calculator

What It Does

This calculator turns four measurements and three choices into a daily calorie target. It estimates resting expenditure with the Mifflin–St Jeor equation, multiplies it by the activity level you select to reach maintenance expenditure, then applies your goal and pace. It also projects what that pace does over the period you set, splits the target between protein, carbohydrate and fat, and prints the intake floor the convention names. Every figure is an estimate: the equation was fitted to population data, and its error for one person is larger than the last digit of its output.

Real-World Usage

Use it when a goal needs a number rather than a rule of thumb: a checkup conversation, a training block with a weight class, or a first attempt to move weight that starts from what you actually eat at maintenance. Re-run it every four to six weeks, because maintenance expenditure falls as body mass falls — the target that held at 80 kg is too high at 74 kg. Keep the pace moderate: the sleep, training and appetite cost of a large deficit is paid for weeks after the number looks good.

Local Context

The energy arithmetic is universal: 7,700 kcal per kilogram and 3,500 kcal per pound of body mass, with the Mifflin–St Jeor equation that US and EU dietetic practice uses. The intake floor travels less well than the arithmetic — public guidance in the United States and the United Kingdom names roughly 1,200 kcal for women and 1,500 for men as the point below which supervision is expected, while some commercial pages print 1,800 for men. This calculator states the convention it uses and names it as a convention. Food labels are quoted in Calories (kcal) with kJ beside them in the United States, and in kcal with kJ beside them across the EU and the UK.

How to read the target over time

The target is a starting point, not a fixed number. Maintenance expenditure falls as body mass falls, so the deficit that produced a 0.5 kg week at 80 kg produces a smaller one at 74 kg: re-run the calculation every four to six weeks, or after any change in activity. The projected change is a straight line by construction, while real progress steps — it holds for a fortnight, flattens around a holiday, then resumes. Use the projection to judge whether a pace is realistic for the period you are willing to hold, not to predict a weigh-in on a particular date.

What the estimate cannot know

The Mifflin–St Jeor equation predicts resting expenditure for a population, and individuals sit either side of that prediction; measured differences of a few hundred calories a day are ordinary. The activity multipliers are self-reported categories, and most people place themselves one level above where the arithmetic would. The macro split is a convention, not a personal prescription: protein needs scale with body mass and training, not with a fixed share of calories. None of it accounts for medication, thyroid conditions, pregnancy, or a training load that changes weekly. A target under the published floor, or a weight change faster than about 1 kg a week, belongs in a conversation with a clinician.

How many calories should I eat to lose weight?

Losing about 0.5 kg (1 lb) a week needs a daily deficit of roughly 550 kcal below your maintenance figure. If your maintenance is 2,670 kcal, the target lands near 2,120 kcal a day. A larger deficit moves the number faster on paper and is harder to hold, and it can push the target under the intake floor this calculator states.

What is the difference between BMR, TDEE and my calorie target?

BMR is the energy you would use at complete rest, TDEE is that figure multiplied by your activity level, and the target is TDEE plus the daily change your goal and pace describe. The result prints all three separately, so you can see which input moved which number.

Is a 1,200 calorie diet safe?

That figure is not a recommendation; it is the floor a common convention names for adult women (1,500 kcal for men), and this calculator reports it rather than applying it. Intakes at or below it are usually supervised, because protein, micronutrient and fibre needs are hard to cover in that budget. Speak to a clinician before planning an intake that low.

Why is the projected weight change only an estimate?

The projection converts a weekly pace into energy at 7,700 kcal per kilogram of body mass, the constant the mainstream pages publish. Real change depends on body composition, adherence, water and how expenditure itself falls as you lose mass, so read the number as a direction and a rate rather than a promise.