BMR, your basal metabolic rate, is the number of calories your body burns at complete rest to keep you alive. TDEE, your total daily energy expenditure, is everything you burn in a day: your BMR plus digesting food, moving around and exercise. Your TDEE is always higher than your BMR, and it's the number to set your calories from.
Both show up in almost every calorie and macro calculator, and they're easy to mix up.
What BMR measures
Even lying in bed all day, your body burns energy to keep your heart beating, your lungs breathing, your brain working and your cells repairing themselves. That baseline is your BMR. For most adults, it's between about 1,200 and 2,000 calories a day.
BMR depends mostly on your size and how much lean mass you carry. Bigger bodies burn more, and muscle burns more than fat. One study of how much each tissue burns put muscle at about 6 calories per pound a day (13 per kilogram) and fat at about 2 calories per pound (4.5 per kilogram). Your organs, especially your brain, liver, heart and kidneys, burn far more per pound than either.
You'll also see RMR, resting metabolic rate. Researchers measure it under slightly less strict conditions than BMR and usually comes out a little higher. In practice, most calculators treat the two as the same thing.
What TDEE measures
TDEE adds everything else you burn in a day on top of your BMR:
| Part | What it covers | Share of TDEE |
|---|---|---|
| BMR | Keeping your body running at rest | About 60 to 70% |
| Thermic effect of food (TEF) | Digesting and absorbing what you eat | About 10% |
| Exercise | Planned workouts, sports, runs | Varies a lot |
| NEAT | Everything else: walking, standing, chores, fidgeting | Varies a lot |
The last two are where people differ the most. NEAT, short for non-exercise activity thermogenesis, can be hundreds of calories a day apart for two people of the same size. Someone with a desk job who drives everywhere and someone who works on their feet can have different TDEEs even if their BMRs are close. For more on raising it, see How many steps a day to lose weight?
How BMR is calculated
Measuring BMR takes a lab, so most people estimate it with a formula. Most calculators use the Mifflin-St Jeor equation, published in 1990. A review that compared the common formulas against measured resting calories found it was the most accurate for most adults, usually landing within about 10% of the real number.
- Men: BMR = (4.54 × weight in pounds) + (15.88 × height in inches) − (5 × age) + 5
- Women: BMR = (4.54 × weight in pounds) + (15.88 × height in inches) − (5 × age) − 161
The original equation uses kilograms and centimeters. The versions above give the same answer in pounds and inches.
How TDEE is calculated
To estimate TDEE, you multiply your BMR by an activity factor that matches a normal week for you:
| Activity level | What it looks like | Multiply BMR by |
|---|---|---|
| Sedentary | Desk job, little exercise | 1.2 |
| Lightly active | Light exercise 1 to 3 days a week | 1.375 |
| Moderately active | Training 3 to 5 days a week | 1.55 |
| Very active | Hard training 6 to 7 days a week | 1.725 |
| Extra active | Physical job plus daily training | 1.9 |
It's easy to pick a level higher than where you are, so if you're torn between two, the lower one is usually closer.
A worked example
Take a 35-year-old woman who is 5 feet 5 inches (165 cm) tall and weighs 160 lb (73 kg):
- 4.54 × 160 = 726
- 15.88 × 65 = 1,032
- 5 × 35 = 175
- BMR = 726 + 1,032 − 175 − 161 = about 1,420 calories
At each activity level, her TDEE comes to:
| Activity level | TDEE | Above her BMR |
|---|---|---|
| Sedentary | About 1,700 | About 280 |
| Lightly active | About 1,950 | About 530 |
| Moderately active | About 2,200 | About 780 |
| Very active | About 2,450 | About 1,030 |
With the same body and the same BMR, her TDEE spreads across 750 calories depending on how much she moves. Pick your activity level with care, since it moves your number more than anything else you enter. Our free Macro, TDEE & BMR Calculator has a TDEE mode and a BMR mode if you only want one of the numbers, and a Macros mode that turns your TDEE into daily targets.
Which number to eat by
Set your calories from your TDEE, since that's what you burn. Eating at your TDEE keeps your weight about the same. Eating below it leads to weight loss, and eating above it leads to weight gain.
Your BMR is a step on the way to TDEE. Eating at or below your BMR is usually a large deficit, because you still burn calories digesting food and moving around. For most people, a deficit of about 300 to 500 calories below TDEE is easier to keep up and helps you keep more muscle. See How to count calories to lose weight for the full process, or How to bulk if you're going the other way.
Why your real numbers may differ
Every formula gives an estimate. Two people with the same age, height and weight can burn different amounts because of muscle mass, genetics, sleep, and how much they move without noticing.
You can find your real TDEE by testing it. Eat a steady amount for two or three weeks, track your weight, and look at the trend. If your weight holds steady, you're eating close to your TDEE. If it goes down or up, you're below or above it.
Your numbers also change over time. As you lose weight, both your BMR and TDEE go down, because a smaller body costs less to run. As you build muscle, they go up a little. Running your numbers again every 10 to 15 lb (5 to 7 kg) of change keeps your targets close.
Common questions
Is it OK to eat less than my BMR?
For short periods under a doctor's care, some people do. For most people trying to lose weight, eating below BMR is a bigger deficit than they can keep up, and it makes it harder to hold on to muscle. A moderate deficit below your TDEE is easier to stick with.
Does lifting weights raise my BMR?
A little. Muscle burns about three times as many calories at rest as fat does, so adding muscle raises your BMR, but only by a few calories a day for each pound. Lifting does more for your body composition and strength than for your BMR.
Does my fitness tracker measure my TDEE?
It estimates it. Wrist trackers count steps and heart rate well, but studies have found their calorie estimates can be well off. Treat the number as a rough guide and let your weight trend show you the real answer.
What does TEF mean?
TEF stands for the thermic effect of food, the calories you burn digesting your meals. Protein takes the most energy to digest, followed by carbs and then fat. TDEE, BMR, TEF and NEAT all have entries in our Fitness Dictionary.
Sources
- Mifflin M.D. et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition (1990).
- Frankenfield D. et al. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association (2005).
- Levine J.A. Nonexercise activity thermogenesis (NEAT): environment and biology. American Journal of Physiology - Endocrinology and Metabolism (2004).
- Wang Z. et al. Specific metabolic rates of major organs and tissues across adulthood: evaluation by mechanistic model of resting energy expenditure. American Journal of Clinical Nutrition (2010).
- Shcherbina A. et al. Accuracy in wrist-worn, sensor-based measurements of heart rate and energy expenditure in a diverse cohort. Journal of Personalized Medicine (2017).
