The difference between BMR (calories at rest) and TDEE (total daily calories burned), the Mifflin-St Jeor formula explained with a worked example, and how to use these numbers for weight loss or muscle gain.
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest, just to keep you alive — breathing, circulating blood, maintaining body temperature, and basic cell function. It does not include any movement, digestion of food, or exercise.
Think of BMR as the calorie cost of simply existing for 24 hours if you stayed in bed the entire time. It's typically the largest component of your total daily calorie burn, even for active people.
There are several formulas for estimating BMR, but Mifflin-St Jeor (1990) is widely regarded as one of the more accurate options for most healthy adults, and is the formula used in our calculator:
| Sex | Formula |
|---|---|
| Men | BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 |
| Women | BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161 |
Get your Basal Metabolic Rate using the Mifflin-St Jeor formula.
Open BMR Calculator →TDEE (Total Daily Energy Expenditure) takes your BMR and multiplies it by an activity factor that reflects how much you move during the day:
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Little to no exercise | BMR × 1.2 |
| Lightly active | Light exercise 1-3 days/week | BMR × 1.375 |
| Moderately active | Moderate exercise 3-5 days/week | BMR × 1.55 |
| Very active | Hard exercise 6-7 days/week | BMR × 1.725 |
| Super active | Very hard training, physical job | BMR × 1.9 |
Sarah, a 30-year-old woman who weighs 65kg and is 165cm tall, moderately active:
| Step | Calculation | Result |
|---|---|---|
| BMR | (10 × 65) + (6.25 × 165) − (5 × 30) − 161 | 1,370 calories/day |
| TDEE | 1,373 × 1.55 (moderately active) | ~2,124 calories/day |
So Sarah burns roughly 1,370 calories just existing, and around 2,124 calories total on a typical moderately active day — the gap between those two numbers (about 754 calories) represents what her daily movement and exercise add on top of her baseline.
Get your full daily calorie burn including activity level — useful for any weight goal.
Open TDEE Calculator →For a precise look at how to split those calories across protein, carbs and fat, see our guide on calculating macros for your specific goal.