Why does my result differ from other calculators?

Formulas differ (Harris-Benedict, Mifflin-St Jeor, Katch-McArdle) and so do activity factors. Gaps of 100 to 200 kcal are normal; what matters is tracking your real weight over a few weeks.

Should I eat less on rest days?

Not necessarily: the activity factor is a weekly average. Keeping the same intake every day is simpler and just as effective, except for very specific training programmes.

Can I go below 1,200 kcal to go faster?

Not without medical supervision. Below that it becomes hard to cover protein, iron, calcium and vitamin needs, and muscle loss speeds up. A moderate, steady deficit gives better results a year on.

Are all calories equal?

For weight, the calorie balance is what counts. For health and fullness, no: protein, fibre and minimally processed foods satisfy more for the same calories, which makes a deficit easier to keep.

Free

Calorie calculator

Enter your profile and activity level: the tool works out your basal metabolic rate, your maintenance needs and a realistic daily calorie target, with the matching macronutrients.

Free, no sign-up, nothing stored

Calorie calculator

How it works

Basal metabolic rate is calculated with the Mifflin-St Jeor equation (1990), which the Academy of Nutrition and Dietetics considers the most reliable for adults: 10 × weight + 6.25 × height − 5 × age, plus 5 for men and minus 161 for women. It is the energy your body spends at complete rest, to breathe, keep its temperature and run its organs.
Maintenance needs multiply that figure by an activity factor, from 1.2 (sedentary) to 1.9 (very active). Most people overestimate their level: if you work seated and train twice a week, “light” is the right choice.
A kilo of body fat holds about 7,700 kcal. A deficit of 550 kcal a day loses close to 0.5 kg a week, a pace considered sustainable; beyond it, muscle loss and tiredness increase. To gain weight the same logic applies as a surplus, ideally with strength training.
Macronutrients are split as a percentage of calories: 4 kcal per gram of protein or carbohydrate, 9 kcal per gram of fat. The “high protein” split (1.6 to 2 g per kilo) helps preserve muscle while losing weight.
These figures are an estimate to within ±10%. Weigh yourself once a week at the same time and adjust by 100 to 200 kcal if your weight does not move the way you want after three weeks. During pregnancy or breastfeeding, with diabetes or an eating disorder, the target should be set with a professional.

These tools give general information. They do not replace the advice of a doctor or a qualified professional.

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Frequently asked questions

Why does my result differ from other calculators?: Formulas differ (Harris-Benedict, Mifflin-St Jeor, Katch-McArdle) and so do activity factors. Gaps of 100 to 200 kcal are normal; what matters is tracking your real weight over a few weeks.
Should I eat less on rest days?: Not necessarily: the activity factor is a weekly average. Keeping the same intake every day is simpler and just as effective, except for very specific training programmes.
Can I go below 1,200 kcal to go faster?: Not without medical supervision. Below that it becomes hard to cover protein, iron, calcium and vitamin needs, and muscle loss speeds up. A moderate, steady deficit gives better results a year on.
Are all calories equal?: For weight, the calorie balance is what counts. For health and fullness, no: protein, fibre and minimally processed foods satisfy more for the same calories, which makes a deficit easier to keep.

How it works

Frequently asked questions

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