What is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body needs to maintain basic life functions — breathing, circulation, cell production and organ function — while completely at rest. Think of it as the energy your body would burn if you lay in bed and did absolutely nothing for 24 hours.
BMR is calculated using formulas that account for age, sex, height and weight. The Mifflin-St Jeor equation is currently considered the most accurate for most adults:
Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
What is TDEE?
TDEE (Total Daily Energy Expenditure) is the total number of calories you burn in a day, including all physical activity. It's your BMR multiplied by an activity factor:
| Activity Level | Multiplier | Example |
|---|---|---|
| Sedentary | × 1.2 | Desk job, no exercise |
| Lightly active | × 1.375 | 1–3 workouts/week |
| Moderately active | × 1.55 | 3–5 workouts/week |
| Very active | × 1.725 | Hard training 6–7 days/week |
| Extremely active | × 1.9 | Physical job + daily training |
Which Number Should You Use?
Use TDEE for all practical diet and weight decisions. BMR alone is useless for meal planning because virtually no one is completely sedentary. Your TDEE is your actual energy budget.
- Weight loss: eat TDEE − 300–500 kcal
- Maintenance: eat exactly TDEE
- Muscle gain: eat TDEE + 250–350 kcal
BMR is useful for understanding your metabolic baseline — for example, if you're going through a very low calorie diet, you should never eat below your BMR for extended periods, as this risks muscle loss and metabolic damage.
Why TDEE Changes Over Time
Your TDEE is not fixed. It decreases as you lose weight (you're carrying less mass), and it can decrease further due to metabolic adaptation — the body's response to prolonged caloric restriction. This is why recalculating TDEE every 4–6 weeks during a diet is important.