BMR vs TDEE: What's the Difference?
If you want to manage your weight, you need to understand two numbers. BMR (Basal Metabolic Rate) is the number of calories your body burns just to stay alive at complete rest: breathing, circulating blood, and maintaining body temperature. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor, giving you your total daily calorie burn including exercise and everyday movement. TDEE is the number you actually need for setting a calorie target.
| Dimension | BMR | TDEE |
|---|---|---|
| Definition | Calories burned at complete rest | Total calories burned per day (includes activity) |
| Formula | Mifflin-St Jeor or Harris-Benedict equation | BMR x activity multiplier (1.2 to 1.9) |
| Reflects | Resting energy needs only | Full daily energy needs |
| Used for | Medical baselines, clinical nutrition | Setting calorie targets for weight goals |
| Typical value (adult) | 1,400-1,800 kcal/day | 1,800-3,000+ kcal/day |
What Is BMR?
Your basal metabolic rate is the floor of your calorie needs. It accounts for roughly 60-75% of your total energy expenditure. BMR depends on your age, sex, height, and weight. Muscle tissue burns more calories at rest than fat tissue, so two people with the same weight can have very different BMRs if their body compositions differ. The most widely validated formula is the Mifflin-St Jeor equation: for men, BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5; for women, subtract 161 instead of adding 5. Use the BMR Calculator to get your number in seconds.
What Is TDEE?
TDEE builds on BMR by accounting for how active you are. It is calculated by multiplying BMR by an activity factor:
- Sedentary (little or no exercise): BMR x 1.2
- Lightly active (1-3 days of exercise per week): BMR x 1.375
- Moderately active (3-5 days per week): BMR x 1.55
- Very active (6-7 days per week): BMR x 1.725
- Extra active (physical job + training): BMR x 1.9
TDEE represents maintenance calories: eating at TDEE keeps your weight stable. Eating below TDEE creates a calorie deficit for fat loss; eating above creates a surplus for muscle gain. Use the TDEE Calculator to find your maintenance number and set a goal-based calorie target.
Key Differences
- Practical use: You will almost never eat at BMR. Eating only your BMR calories would leave no fuel for any physical activity and is well below healthy intake for most people. TDEE is the actionable number.
- What changes each: BMR changes slowly with age, weight loss, or significant muscle gain. TDEE can change day to day based on how active you are.
- Accuracy: Both are estimates. Individual metabolism varies by up to 10-15%. Track your actual weight for several weeks and adjust calories if the predicted trend does not match reality.
Which Should You Use?
Calculate your BMR first to establish a baseline. Then apply your activity multiplier to get your TDEE, which is the number you will use for any calorie goal. For weight loss, a common starting point is a 500 kcal/day deficit below TDEE, which produces roughly 1 lb of fat loss per week. For muscle gain, a 200-300 kcal/day surplus above TDEE is a common conservative approach.
FAQ
Does BMR decrease when I diet?
Yes. Prolonged calorie restriction causes adaptive thermogenesis: your body lowers BMR to conserve energy. This is why weight loss often slows over time even at the same calorie intake. Preserving muscle mass through resistance training can help limit this adaptation.
Should I eat back calories burned during exercise?
If you use a TDEE approach with an activity multiplier, exercise is already baked into your calorie target and you should not add calories back. If you use a sedentary TDEE and log workouts separately, eating back a portion of exercise calories is reasonable.
Which BMR formula is most accurate?
The Mifflin-St Jeor equation is generally considered the most accurate for the general population. The Katch-McArdle formula can be more accurate if you know your lean body mass, because it accounts for body composition directly.