BMR vs TDEE: How Many Calories Do You Really Burn?

BMR is the energy your body uses at rest. TDEE is your estimated total daily energy use, which adds the energy you spend on activity and daily movement to your BMR. BMR tells you the base. TDEE tells you the total. This guide explains both numbers, shows a worked example with two formulas and explains how to use TDEE for a calorie target. These are estimates, not a diagnosis.

What BMR means

Basal metabolic rate (BMR) is the energy used to keep you alive at rest. It covers breathing, circulation, brain activity and the work of keeping your body temperature steady. You do not feel it, but it is the largest part of most people's daily use.

BMR depends on body size, age and sex. A taller and heavier body uses more energy at rest. Muscle uses more energy than fat, so body composition also matters, but most calculators use weight, height and age.

What TDEE means

Total daily energy expenditure (TDEE) is BMR plus everything else you do in a day. This includes walking, work, exercise, the energy used to digest food and small movements such as fidgeting. A simple estimate multiplies BMR by an activity factor.

The factors are rough groups. Choose the one that best matches your normal week, not your best week.

The Mifflin-St Jeor formula

The Mifflin-St Jeor equation is a common way to estimate BMR. It uses weight in kilograms, height in centimeters and age in years:

• Men: BMR = 10 × weight + 6.25 × height − 5 × age + 5
• Women: BMR = 10 × weight + 6.25 × height − 5 × age − 161

Worked example 1: a man

A man is 30 years old, weighs 80 kg and is 180 cm tall. He exercises three days a week, which fits the moderate factor of 1.55.

1. BMR: 10 × 80 = 800, plus 6.25 × 180 = 1,125, minus 5 × 30 = 150, plus 5. Total: 1,780.
2. TDEE: 1,780 × 1.55 = 2,759.

His estimated BMR is 1,780 calories a day, and his estimated TDEE is about 2,759 calories a day.

Worked example 2: a woman

A woman is 30 years old, weighs 65 kg and is 165 cm tall. She is lightly active, so the factor is 1.375.

1. BMR: 10 × 65 = 650, plus 6.25 × 165 = 1,031.25, minus 150, minus 161. Total: 1,370.25.
2. TDEE: 1,370.25 × 1.375 = 1,884.1.

Her estimated BMR is about 1,370 calories, and her estimated TDEE is about 1,884 calories a day.

The Katch-McArdle formula

The Katch-McArdle formula works from lean body mass instead of total weight:

BMR = 370 + 21.6 × lean body mass in kg

It can suit people who know their lean mass well. It needs a reliable estimate of body composition, so the result is only as good as that input.

Using TDEE for a calorie target

Eating less than your TDEE leads to a calorie deficit. Eating more leads to a surplus. Many people use a moderate deficit when they want to lose weight, because large deficits are hard to keep and can leave you tired or hungry.

Weigh yourself over several weeks, not each day. If your weight does not change as expected, adjust your intake and check again after two or three weeks. For a large change in diet, or if you have a medical condition, ask a doctor or dietitian first.

Remember that TDEE is an estimate. Sleep, stress, illness and daily habits all change your real use.

Why two calculators give different numbers

The formula, the weight input and the activity factor all change the answer. Mifflin-St Jeor and Katch-McArdle use different inputs, so their BMR values can differ for the same person. Choose one formula, use it for a few weeks and track the results. A single calculator number is a starting point, not a final answer.

How Metabolica does it

Metabolica calculates BMR, TDEE and BMI from your age, height, weight and activity level. It offers three formulas: Mifflin-St Jeor, Harris-Benedict and Katch-McArdle. You can choose the formula that fits your body and switch at any time.

The app also offers eight nutrition profiles, a food log with a database of more than 100 everyday foods, workout plans and progress charts. Metabolica PRO adds eight advanced analysis modules, including a NEAT Analyzer and an EPOC Tracker. These modules show estimates for information only. They do not diagnose a condition.

For the full feature list, see the Metabolica app page. You can compare other tools on the apps page.

If you want to see your own numbers, open Metabolica and enter your details. Use the result as a starting point, and check it against your weight over time.

Frequently asked questions

Is TDEE the same as my daily calorie target?

Not always. TDEE is an estimate of what you use. A calorie target is the number you eat each day, which may be above or below TDEE depending on your goal.

Which formula is the most accurate?

No single formula fits everyone. Mifflin-St Jeor is widely used for the general population. Katch-McArdle can suit people with a reliable lean mass estimate. Track your weight over several weeks to see which estimate fits you.

Why does my weight change differently from the estimate?

Water, sleep, stress and the measurement of your activity all change the result. Look at the trend over several weeks rather than one day.

Should I eat exactly my BMR to lose weight?

No. Eating at BMR is very low and is not a sensible plan for most people. A moderate deficit below TDEE is more common. Ask a doctor or dietitian before a large change.