What is the difference between BMR and TDEE?

BMR is what your body burns at complete rest — as if you stayed in bed all day. TDEE includes your BMR plus the energy spent on everything else you do (walking, working, training). TDEE is always higher than BMR.

How often should I recalculate my BMR?

Recalculate whenever your weight changes significantly (5 kg or more), on each birthday (BMR declines with age), or when your activity level changes. In practice, once every 2–3 months is enough for most people.

Is the Mifflin-St Jeor formula accurate?

It is the most accurate of the popular estimation equations, with a margin of error of about 10% for most of the population. Exact figures require indirect calorimetry testing. But for building a starting nutrition plan, it is more than good enough.

Can I eat less than my BMR to lose weight faster?

It is not recommended. Eating consistently below your BMR can slow your metabolism and cause muscle loss, fatigue and nutrient deficiencies. This calculator already applies a safety floor (1,500 kcal for men, 1,200 kcal for women) to avoid that risk.

How do I count calories in practice without weighing everything?

Use an app like Nutricalor: photograph your plate and the AI estimates calories and macros in seconds. It is far faster than weighing ingredients or searching through databases.

BMR Calculator — Basal Metabolic Rate and Daily Calorie Burn

What Basal Metabolic Rate (BMR) is

Your Basal Metabolic Rate, or BMR, is the minimum amount of energy your body needs to keep its vital functions running at complete rest: breathing, blood circulation, temperature regulation, brain activity and cell renewal. Even if you spent the whole day lying down without moving, your body would still burn that energy.

BMR accounts for roughly 60% to 75% of total daily calorie expenditure. That makes it the starting point for any eating plan — whether you want to lose weight, maintain it or build muscle. Without knowing your BMR, any calorie target is guesswork.

How BMR is calculated

This calculator uses the Mifflin-St Jeor equation, published in 1990 and considered the most accurate of the popular estimation formulas. It accounts for weight, height, age and biological sex:

• Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5 • Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161

The difference between men and women reflects the higher average proportion of lean mass in male bodies, which demands more energy at rest. The formula produces an estimate — for exact figures you would need indirect calorimetry testing in a lab.

BMR, TDEE and calorie burn: the difference

These are three related but distinct numbers:

• BMR (Basal Metabolic Rate): what your body burns at complete rest, with no movement at all. • TDEE (Total Daily Energy Expenditure): what you actually burn given everything you do in a day — walking, working, training. It is calculated by multiplying BMR by an activity factor. • Calorie target: how much you should eat to reach a specific goal. To lose weight, the target sits below your TDEE (a deficit). To gain weight, above it (a surplus).

Most people confuse BMR with TDEE. If you eat only your BMR you will create a deficit — but it may not be a healthy one, depending on your activity level. That is why this calculator shows all three figures.

What to do with this number

Now that you have your BMR, your TDEE and a target per goal, the next step is adjusting how you eat:

• To lose weight: eat below your TDEE (the calculator suggests −20%, a moderate and sustainable deficit). Never go below the safety floor (1,500 kcal for men, 1,200 kcal for women) without professional supervision. • To maintain: eat close to your TDEE. Swings of 100–200 kcal are normal and expected. • To gain muscle: eat above your TDEE (+10% is a mild surplus that favors muscle gain with less fat storage).

Remember: these are estimates. The body is not a spreadsheet. Use them as a starting point, watch what happens on the scale and in the mirror over several weeks, and adjust. And whenever you can, work with a registered dietitian.

Frequently asked questions

What is the difference between BMR and TDEE?: BMR is what your body burns at complete rest — as if you stayed in bed all day. TDEE includes your BMR plus the energy spent on everything else you do (walking, working, training). TDEE is always higher than BMR.
How often should I recalculate my BMR?: Recalculate whenever your weight changes significantly (5 kg or more), on each birthday (BMR declines with age), or when your activity level changes. In practice, once every 2–3 months is enough for most people.
Is the Mifflin-St Jeor formula accurate?: It is the most accurate of the popular estimation equations, with a margin of error of about 10% for most of the population. Exact figures require indirect calorimetry testing. But for building a starting nutrition plan, it is more than good enough.
Can I eat less than my BMR to lose weight faster?: It is not recommended. Eating consistently below your BMR can slow your metabolism and cause muscle loss, fatigue and nutrient deficiencies. This calculator already applies a safety floor (1,500 kcal for men, 1,200 kcal for women) to avoid that risk.
How do I count calories in practice without weighing everything?: Use an app like Nutricalor: photograph your plate and the AI estimates calories and macros in seconds. It is far faster than weighing ingredients or searching through databases.

Other calculators

Calorie Deficit Calculator

Find out how many calories to eat to lose weight at your own pace.

Daily Calorie Calculator

Find out how many calories to eat to lose, maintain or gain.

BMI Calculator

Calculate your Body Mass Index and see your WHO category.

Macro Calculator

Split your calories into protein, fat and carbs.