BMR vs TDEE

BMR stands for Basal Metabolic Rate. It is the calories your body burns at complete rest, just keeping you alive. Breathing, blood flow, body temperature, brain activity, and basic cell function all draw on BMR.

If you stayed in bed for a full 24 hours, did not exercise, did not eat, and barely moved, BMR is roughly what you would burn. For most healthy adults, BMR sits in the range of 1,200 to 2,000 calories per day, depending on sex, age, height, and weight.

The most widely used BMR formula is Mifflin-St Jeor:

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

For a quick estimate that handles unit conversions, the BMR calculator does the math in one step.

TDEE stands for Total Daily Energy Expenditure. It is an estimate of how many calories your body burns in a normal day after you account for movement, exercise, and the energy used to digest food. For a longer plain-language overview, see What Is TDEE?.

The formula has two pieces:

TDEE = BMR × activity factor

The activity factor is a multiplier that scales BMR up to match your real-world life:

• Sedentary (1.2): little or no exercise, mostly desk work.
• Light (1.375): light exercise 1 to 3 days per week.
• Moderate (1.55): moderate exercise 3 to 5 days per week.
• Very active (1.725): hard exercise 6 to 7 days per week.
• Extra active (1.9): physically demanding job, daily training, or both.

The TDEE calculator runs both steps and shows your maintenance, weight-loss, and weight-gain calorie targets at the same time.

The single difference: BMR is your resting calorie burn. TDEE is BMR plus everything else.

Both are estimates of energy use. BMR sits at the bottom (a metabolic floor). TDEE sits above it (the floor plus a multiplier for activity). If you eat at your TDEE, your weight stays roughly the same on average. If you eat at your BMR alone, you would lose weight quickly because you would not be eating enough to fuel a normal day.

TDEE includes things BMR does not:

• Walking around at home or work.
• Standing, fidgeting, household chores.
• Exercise sessions.
• The thermic effect of food (calories your body burns digesting what you eat).

Even sedentary office workers have a TDEE that is about 20 percent higher than their BMR (the 1.2 multiplier). Active people see a much bigger gap: a moderate multiplier of 1.55 means TDEE is 55 percent higher than BMR.

If your TDEE looks identical to your BMR, the activity factor was not applied.

Use TDEE. To lose weight, eat 250 to 500 calories below your TDEE per day, which works out to roughly half a pound to one pound per week.

Eating below your BMR for any extended period is generally not recommended. It is a very large deficit that is hard to sustain, makes hunger and fatigue worse, and tends to backfire. The standard advice is to keep your calorie intake at or above BMR even during a cut.

If you also want to compare your current weight to the standard healthy range for your height, the BMI calculator gives you a separate point of reference.

Use TDEE. Maintenance means eating roughly the same number of calories your body burns. By definition, that is your TDEE.

Because TDEE is an estimate, plan to track for two to three weeks and adjust based on what your weight actually does. If the scale stays flat, you have your maintenance number. If it drifts, nudge calories up or down by 100 to 200 per day until things stabilize.

Use TDEE. To build muscle, eat slightly above your TDEE. A surplus of 200 to 400 calories per day is enough for most lifters, paired with adequate protein (around 1.6 to 2.2 grams per kilogram of body weight per day) and a serious training plan.

Larger surpluses tend to add more fat than muscle, especially for people who are not brand new to lifting.

Once you have a daily calorie target, the macro calculator splits it into protein, carbs, and fat in grams.

Take a 30-year-old man, 180 lb (about 82 kg), 5 ft 10 in (about 178 cm), with a moderate activity level.

1. BMR (Mifflin-St Jeor): 10 × 82 + 6.25 × 178 − 5 × 30 + 5 = about 1,788 calories
2. Activity factor: 1.55 (moderate)
3. TDEE: 1,788 × 1.55 = about 2,770 calories per day

Same person, two numbers:

For a step-by-step walkthrough of the same calculation, see How to Calculate TDEE.

Both BMR and TDEE come from population formulas, not direct measurement. Real BMR can vary by 10 percent or more from the formula, even between two people with the same height, weight, age, and sex. Differences in muscle mass, sleep, stress, and tracking accuracy all add error.

The activity multiplier is rougher still. It tries to capture an entire week of behavior in a single number, and most people pick a multiplier one step too high.

Plan for the numbers to be a starting point. After two to three weeks of eating at your target, the scale will tell you whether to adjust up or down.

A side-by-side view of the two numbers and how they differ in practice: