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Health

Calorie & BMR Calculator

Calculate your Basal Metabolic Rate (BMR) and daily calorie needs based on your activity level and goal.

Knowing how many calories you need each day is the starting point for any body composition goal: losing fat, gaining muscle or maintaining your current weight. This calculator starts from the Basal Metabolic Rate (BMR) — the energy your body burns at rest — and multiplies it by your activity factor to get your Total Daily Energy Expenditure (TDEE).

Based on your TDEE and goal, the calculator works out your recommended daily calorie intake and provides an indicative macronutrient breakdown: protein, carbohydrates and fat. It uses the Mifflin-St Jeor formula, considered the most accurate for the general population.

Your data

BMR (at rest)

1699

kcal/día

TDEE (with activity)

2633

kcal/día

Daily target

2633

kcal/día

Daily macros — Maintain weight

197g

Protein

30% · 4 kcal/g

263g

Carbs

40% · 4 kcal/g

88g

Fat

30% · 9 kcal/g

Standard indicative distribution. Adjust according to your diet and specific goals.

Values are population estimates. Consult a nutritionist or dietitian before making significant changes to your diet.

How your daily calories are calculated

The calculation happens in three steps. First, your Basal Metabolic Rate (BMR) is estimated with the Mifflin-St Jeor equation, which only needs your weight, height, age and biological sex. Then the BMR is multiplied by an activity factor (from 1.2 if you are sedentary to 1.9 if you train daily and have a physical job) to get your Total Daily Energy Expenditure or TDEE. Finally, the adjustment for your goal is added or subtracted: a deficit of around 500 kcal to lose about 0.5 kg of fat per week, or a moderate surplus of 300 kcal to gain muscle while minimising fat gain.

Worked example

For a 30-year-old man, 75 kg and 175 cm, moderately active (factor 1.55): the BMR is 10×75 + 6.25×175 − 5×30 + 5 = 1,699 kcal. Multiplied by 1.55, that gives a TDEE of about 2,633 kcal, which is what he would need to maintain his weight. To lose fat he would subtract 500 kcal and eat around 2,133 kcal a day; to gain muscle he would add 300 kcal, up to about 2,933 kcal.

Physical activity factors

FactorLevelWho it applies to
1.2SedentaryDesk job, driving everywhere and no planned exercise.
1.375Lightly activeLight exercise or sport 1–3 days per week.
1.55Moderately activeModerate exercise 3–5 days per week.
1.725Very activeIntense exercise 6–7 days per week.
1.9Extra activeDemanding physical job combined with daily training.

How to interpret the result

The number you get is a starting point, not an exact, fixed figure. The best way to use it is to keep that calorie intake for 2 to 3 weeks and weigh yourself under the same conditions each time: if your weight moves in line with your goal, the estimate is right; if it doesn't budge, adjust by ±100–150 kcal and observe again. Remember the scale fluctuates daily due to water, glycogen and gut transit, so watch the weekly trend rather than a single day's reading.

Frequently asked questions

The Basal Metabolic Rate is the minimum energy your body needs at absolute rest to maintain vital functions: breathing, circulation, body temperature, etc. It represents 60–75% of total calorie expenditure.

It uses the Mifflin-St Jeor formula (1990), considered the most accurate for the general population: male: 10×weight + 6.25×height − 5×age + 5; female: 10×weight + 6.25×height − 5×age − 161. The result is then multiplied by the activity factor to get TDEE.

Calculators are population estimates. Your metabolism may differ. Factors such as hormonal status, muscle mass, sleep or gut microbiome affect actual expenditure. If you have not progressed for weeks, adjust calories by ±100 kcal and observe the result.

To lose fat you need a calorie deficit — eating fewer calories than you burn. A moderate deficit of 300 to 500 kcal per day below your TDEE lets you lose between 0.3 and 0.5 kg of fat per week, a sustainable pace that preserves muscle mass. Very aggressive deficits (more than 750–1,000 kcal) speed up short-term loss but increase muscle loss, hunger and the risk of giving up. A small deficit maintained over time, alongside enough protein and some strength training, works far better.

Protein is the key macronutrient for preserving and building muscle mass, especially in a calorie deficit. Common recommendations for active people range from 1.6 to 2.2 grams per kilogram of body weight per day. Protein is also the most satiating nutrient and the one that burns the most energy during digestion, which indirectly helps with weight control. This calculator assigns 30% of calories to protein as an indicative starting point; you can adjust it to suit your diet and preferences.

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