How Many Calories Do You Need a Day? BMR and TDEE Explained

Almost every calorie goal starts from one question: how many calories does your body use in a day? The answer has two parts. The first is what your body burns just to stay alive. The second is everything you add by moving around. Together they are called your TDEE, and understanding both makes any calorie target easier to set.

BMR: the calories you burn at rest

BMR stands for basal metabolic rate. It is the energy your body uses at complete rest to keep the basics running: breathing, circulation, body temperature, and the constant repair of cells. For most people it is the largest share of the calories they burn each day, even though none of it feels like effort.

BMR cannot be measured at home, so it is estimated from a few things you do know. One of the most widely used estimates is the Mifflin-St Jeor equation, published in 1990. It takes your weight, height and age, and adjusts for sex.

• Start with 10 × your weight in kilograms.
• Add 6.25 × your height in centimeters.
• Subtract 5 × your age in years.
• Then add 5 if you are male, or subtract 161 if you are female.

TDEE: adding your daily movement

TDEE is total daily energy expenditure: your BMR multiplied by a factor for how active your day is. Using the standard activity factors that go with this equation:

• Sedentary, little or no exercise: BMR × 1.2
• Lightly active, 1–3 days a week: BMR × 1.375
• Moderately active, 3–5 days a week: BMR × 1.55
• Very active, 6–7 days a week: BMR × 1.725
• Extra active, an athlete or a physical job: BMR × 1.9

In PulseLoop Health, the activity level describes your everyday routine, such as walking around, standing and doing chores. Planned workouts you log are added on top of that, so the same exercise is not counted twice.

From TDEE to a calorie goal

If you eat about your TDEE, your weight tends to stay steady. Eating below it is how people aim to lose weight, and above it to gain. A common starting point is to move about 500 calories below or above TDEE, and that is the default PulseLoop Health uses.

Treat that as a place to begin, not a rule. People respond differently, and very low calorie intakes are not safe for everyone. If you have a medical condition, are pregnant or breastfeeding, or are unsure what a safe target is for you, ask a doctor or a registered dietitian.

Why your number is only an estimate

Equations like this are built from averages across many people, so they cannot account for everything about you. Muscle mass, some medications and some medical conditions can all change how much energy a body uses.

The practical fix is simple: use the number for two to three weeks, watch what your weight actually does, and adjust your target up or down from there. Your own results are more reliable than any equation.