BMR vs TDEE: What's the Difference?

BMR and TDEE are the two numbers every calorie plan is built on — and they're also the two numbers people mix up most often. In one line: BMR (Basal Metabolic Rate) is the calories your body burns just to stay alive, and TDEE (Total Daily Energy Expenditure) is your BMR plus everything else you do in a day. Understanding the difference is the difference between a diet that works and one that stalls for weeks.

BMR vs TDEE: the one-line difference

Your body burns energy around the clock. Even if you lay in bed all day — no movement, no exercise — your heart, lungs, brain, and digestion still need fuel. That baseline is your BMR: the number of calories you'd burn in 24 hours doing absolutely nothing.

But nobody does absolutely nothing. You walk to the kitchen, fidget at your desk, climb stairs, go for a run. All of that extra movement costs energy on top of your BMR. Add it all together and you get TDEE — the total number of calories you burn in a typical day.

The relationship is simple:

• BMR = calories burned at complete rest
• TDEE = BMR + daily activity + exercise

TDEE is always larger than BMR. For most people, TDEE runs about 1.2 to 2 times their BMR depending on how active they are.

How BMR is calculated: the Mifflin-St Jeor formula

The most widely trusted formula for estimating BMR is the Mifflin-St Jeor equation, developed in 1990 and still the reference standard used by dietitians. It takes four inputs: sex, weight, height, and age.

For men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5

For women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161

Notice that age is subtracted: BMR declines roughly 1–2% per decade after early adulthood, mostly because muscle mass decreases. Weight and height are added: a bigger body costs more to keep running. And the formula differs by sex because, on average, men carry more muscle and less body fat than women at the same weight — and muscle burns more calories than fat.

No formula is perfect. The Mifflin-St Jeor equation is typically accurate within ±10% for most adults, but it can under- or over-estimate for very muscular or very obese individuals, since it doesn't know your body composition. Still, it's the best free estimate available and far more reliable than generic "2,000 calories a day" advice.

How TDEE is calculated: activity multipliers

To turn BMR into TDEE, you multiply it by an activity factor that matches your lifestyle:

These multipliers are approximations, not physics. If you're between two levels, pick the higher one and track your weight for two to three weeks — if it isn't moving the way you want, adjust.

Worked example: same person, both numbers

Let's run a full example. Meet Sarah: 30 years old, 70 kg (154 lb), 165 cm (5'5"), and she goes to the gym three times a week — moderately active.

Step 1 — BMR (Mifflin-St Jeor, female):

• 10 × 70 = 700
• 6.25 × 165 = 1,031.25
• 5 × 30 = 150
• BMR = 700 + 1,031.25 − 150 − 161 = 1,420 calories/day

Step 2 — TDEE (moderately active multiplier, × 1.55):

• TDEE = 1,420 × 1.55 = 2,201 calories/day

The two numbers tell very different stories. If Sarah ate 1,420 calories, she'd be eating at her resting baseline — effectively a steep deficit. Her actual burn, given her real life, is about 2,200 calories. That's the number that matters for planning.

BMR vs TDEE: side-by-side comparison

Which number should you use for weight loss?

Always plan from TDEE. This is the mistake the confusion causes: people calculate their BMR (say, 1,600), eat at that number, and call it a diet. But if their TDEE is 2,400, eating 1,600 is an 800-calorie deficit — aggressive, hard to sustain, and likely to backfire through fatigue and binges. Worse, some people eat below their BMR, which is unsafe to sustain.

The sane approach for cutting:

1. Calculate your TDEE (the full daily burn).
2. Subtract a moderate deficit — typically 300 to 500 calories per day, which yields roughly 0.5 to 1 lb of fat loss per week.
3. Keep the target above your BMR.

In Sarah's case: TDEE 2,200, minus 400 = 1,800 calories/day for steady fat loss — comfortably above her 1,420 BMR, and sustainable.

Which number for maintenance and muscle gain?

For maintenance, the answer is simply your TDEE: eat at it, and your weight stays roughly stable. For muscle gain (bulking), add a small surplus — about 200 to 300 calories above TDEE — plus resistance training and enough protein. The small surplus favors lean muscle over fat gain; overshooting to +800 mostly adds fat.

One more thing: BMR is still useful as a sanity check. Whatever your goal, your daily intake shouldn't sit below your BMR for extended periods without medical supervision. It also matters when life gets sedentary — on a rest week or an injury, your TDEE drops while your BMR barely changes, so your targets should drop too.

The bottom line

BMR is your engine idling; TDEE is your engine through a whole day of driving. Know both, but set your targets from TDEE: subtract 300–500 calories to lose, eat at it to maintain, and add 200–300 to gain. Skip the hand math and get your exact numbers with our free BMR calculator and TDEE calculator — then check your daily target with the calorie calculator.

Frequently Asked Questions

What is the difference between BMR and TDEE?

BMR is the calories your body burns at complete rest. TDEE is BMR plus all the calories you burn through daily activity, so TDEE is always the larger number.

How is BMR calculated?

With the Mifflin-St Jeor equation, which uses your weight, height, age, and sex to estimate resting calorie burn.

Which number should I use for weight loss?

TDEE. Eating below your TDEE creates a deficit; using BMR alone as a daily intake target would be too low for most people.

Can BMR ever be higher than TDEE?

No. TDEE is BMR plus activity, so it is always equal to or higher than BMR.