BMR vs TDEE — What's the Difference?
BMR is the calories you would burn if you did nothing all day. TDEE is your BMR plus the calories you burn moving, digesting and exercising. TDEE is the number you use to set calorie targets; BMR is the resting floor underneath it.
What is the difference between BMR and TDEE?
BMR (basal metabolic rate) is the energy your body uses purely to stay alive at complete rest — keeping your heart beating, your lungs working and your organs running. It is the single biggest part of your daily burn, usually 60–70% of it. TDEE (total daily energy expenditure) is the whole picture: your BMR plus the calories you spend walking, working, exercising and digesting food. You get from one to the other by multiplying your BMR by an activity factor — that step is covered in how TDEE is calculated.
Where does RMR fit in?
You'll also see RMR (resting metabolic rate), and its synonym REE (resting energy expenditure). BMR is measured under strict lab conditions; RMR under everyday resting conditions, so it runs slightly higher. In practice the two are used interchangeably — the Mifflin-St Jeor equation technically estimates RMR/REE, which is why this and most calculators report the result as your BMR. Full detail in BMR vs RMR.
Which one should you use?
For setting calorie goals — losing, maintaining or gaining weight — use your TDEE, because it reflects what you actually burn in a real day. Your BMR is most useful as a floor: eating far below your resting requirement for long stretches is hard to sustain. To see your own BMR, TDEE and goal targets together, use the calculator, or get just your resting figure from the BMR calculator.