BMR is what your body burns doing absolutely nothing. TDEE is what it burns actually being a person. For planning your eating, TDEE is the number. BMR is the floor — a useful reference, not an eating target.
BMR: the baseline
Basal metabolic rate is the calories your body needs to keep basic functions running — breathing, circulating blood, maintaining body temperature, organ function. If you lay in bed all day, burned nothing digesting food, and didn't move, your BMR is roughly what you'd burn.
For most adults, BMR lands between 1,200 and 1,800 calories per day, depending on sex, age, height, and weight. A 30-year-old 180 lb male has a BMR around 1,780 calories. A 30-year-old 140 lb female is around 1,385.
TDEE: the real number
Total daily energy expenditure is BMR plus everything else:
- NEAT (non-exercise activity thermogenesis) — walking, standing, fidgeting.
- TEF (thermic effect of food) — ~10% of intake, burned digesting what you eat.
- Exercise — structured workouts, weight training, cardio.
A sedentary adult burns ~1.2× BMR total. A moderately active one burns ~1.55×. A very active one burns ~1.9×. The same 180 lb male above might have a TDEE of 2,140 (sedentary), 2,760 (moderately active), or 3,380 (very active).
Which one to use, when
Eat at TDEE for maintenance. Subtract 300–500 for weight loss. Add 200–300 for muscle gain. Never eat below BMR — that's a recipe for metabolic adaptation, muscle loss, and bingeing.
Use BMR as a reference for:
- Minimum safe intake floor.
- Comparing metabolic rate across time (drops with weight loss).
- Estimating resting calorie burn in medical or athletic contexts.
Both BMR and TDEE from age + sex + height + weight + activity. 20 seconds.