BMR and TDEE are the two most important numbers in nutrition science, yet they are frequently confused. Understanding the difference between them — and knowing which one to use — is essential for setting accurate calorie targets whether your goal is weight loss, maintenance, or muscle gain.
BMR: Your Body at Rest
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to keep you alive. It powers your heartbeat, breathing, brain function, cell repair, and organ systems. BMR accounts for 60–75% of the calories most people burn each day. You should never eat below your BMR for an extended period, as this can slow metabolism, cause muscle loss, and create nutritional deficiencies.
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 5 Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161 Example: A 30-year-old man, 180 lbs (81.6 kg), 5’11” (180 cm): BMR = 10(81.6) + 6.25(180) − 5(30) − 5 = 1,791 calories/day.
TDEE: Your Total Daily Burn
Total Daily Energy Expenditure (TDEE) is the total number of calories you burn in a day, including BMR plus all physical activity and the thermic effect of food. TDEE is the number you actually use to set calorie targets.
TDEE = BMR × Activity Multiplier Activity multipliers: Sedentary (1.2), Lightly active (1.375), Moderately active (1.55), Very active (1.725), Extremely active (1.9).
BMR vs TDEE: When to Use Each
| Goal | Use This Number | How |
|---|---|---|
| Weight loss | TDEE | Eat 300–500 calories below TDEE (never below BMR) |
| Weight maintenance | TDEE | Eat at your TDEE |
| Muscle gain | TDEE | Eat 200–400 calories above TDEE |
| Minimum safe intake | BMR | Never eat below your BMR for extended periods |
Calculate both numbers with the TDEE Calculator and the BMR Calculator.
Common Mistakes
- Using BMR as your calorie target. BMR is your minimum, not your target. Eating at BMR means a deficit equal to all your daily activity — too aggressive for most people.
- Overestimating activity level. Most desk workers are sedentary (1.2) even if they exercise 3 times per week. A 30-minute gym session does not make you "very active."
- Ignoring adaptive thermogenesis. After prolonged dieting, your body reduces BMR by 10–15% as a survival mechanism. This is why weight loss plateaus occur and why periodic diet breaks are recommended.
Key Takeaways
- BMR is calories burned at complete rest. It is your metabolic floor — never eat below it.
- TDEE is your total daily calorie burn including activity. This is the number to base your diet on.
- For weight loss, eat 300–500 calories below TDEE, not below BMR.
- Most people overestimate their activity level — start with sedentary and adjust based on actual results.
- Recalculate every 10–15 lbs of weight change, as BMR shifts with body composition.
Frequently Asked Questions
What is a normal BMR for a woman?
BMR for women typically ranges from 1,200 to 1,600 calories per day depending on age, weight, and height. A 30-year-old woman who is 5'5" and 140 lbs has a BMR of approximately 1,400 calories. This means her body burns 1,400 calories daily just to maintain basic life functions at complete rest.
How many calories should I eat to lose weight?
Calculate your TDEE first, then subtract 300-500 calories for a sustainable deficit that produces 0.5-1 lb of fat loss per week. For example, if your TDEE is 2,200 calories, eat 1,700-1,900 calories daily. Never go below your BMR (typically 1,200-1,600 for women, 1,400-1,800 for men).
Does exercise increase BMR?
Exercise does not directly increase BMR during the workout, but building muscle mass through resistance training raises BMR permanently because muscle tissue burns more calories at rest than fat tissue. Each pound of muscle burns roughly 6-7 calories per day at rest, compared to 2 calories per pound of fat.