BMR vs TDEE: What's The Difference?
Understand the key differences between BMR and TDEE, and learn which number you should actually use for your diet planning.
The Simple Answer
BMR (Basal Metabolic Rate) is how many calories your body burns if you stayed in bed all day doing absolutely nothing.
TDEE (Total Daily Energy Expenditure) is how many calories you actually burn in a full day, including walking, working, exercising, and even digesting food.
Think of BMR as your car idling in the driveway. TDEE is your car actually driving around town. The car uses more gas when it's moving, right? Same idea.
Why BMR Alone Isn't Enough
You shouldn't eat based on your BMR alone because you don't lay in bed motionless all day (hopefully!).
Even if you have a desk job and don't exercise, you're still walking to the bathroom, cooking food, climbing stairs, and doing light activities. All of this burns calories beyond your BMR.
If you ate only your BMR calories, you'd likely lose weight unintentionally and feel tired because you're not fueling your actual activity level.
How to Calculate Your TDEE from BMR
To get your TDEE, you multiply your BMR by an activity factor. Here's the simple formula:
Sedentary (little or 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 exercise, physical job): BMR × 1.9
For example, if your BMR is 1,500 and you're lightly active, your TDEE would be 1,500 × 1.375 = 2,063 calories per day.
Which Number Should You Use?
Always use TDEE for your diet planning, not BMR. Here's why:
Your TDEE tells you how much you're actually burning each day, so it's the realistic number to work with.
To lose weight: Eat 300-500 calories less than your TDEE.
To maintain weight: Eat approximately your TDEE.
To gain weight: Eat 300-500 calories more than your TDEE.
Keep BMR in mind as a safety check—never eat below your BMR for extended periods, as this can mess up your metabolism and make you feel terrible.
Real World Example
Let's say Sarah is a 30-year-old woman who works a desk job. Her BMR is 1,400 calories.
She doesn't exercise much, so she's 'sedentary.' Her TDEE would be 1,400 × 1.2 = 1,680 calories per day.
If Sarah wants to lose about 1 pound per week, she should eat around 1,180-1,380 calories per day (creating a 300-500 calorie deficit from her TDEE of 1,680).
Notice she's still eating near or slightly below her BMR (1,400), which is okay for fat loss if done carefully. But she shouldn't go much lower or stay there too long.
After tracking for 2-3 weeks, Sarah checks her results. If she's not losing weight, she might need to adjust her calories or increase activity slightly.