A worked example
Take a woman who is 45, 5’5” (165 cm) and 170 pounds (77 kg). The Mifflin-St Jeor equation for women is 10 × weight in kg + 6.25 × height in cm − 5 × age − 161.
That gives a BMR of about 1,417 calories. If she is lightly active, her TDEE is about 1,417 × 1.375 = 1,948. That second number is roughly her maintenance: what she’d eat to stay the same weight.
Does BMR include walking?
No. BMR is only what your body uses at rest. Your walks, chores and even digesting food are in TDEE. That’s why you don’t eat “just your BMR” to lose weight: your target comes from TDEE, minus a gap.
Why is my BMR so low?
BMR mostly follows body size, age and sex, and the muscle you carry. A smaller, shorter or older person has a lower BMR, and that is normal, not a sign that something is broken.
It is also an estimate. A 2005 review found the Mifflin-St Jeor equation predicted resting metabolism within 10% of the measured value for more people than other equations, but some people fall outside that range. Indirect calorimetry can measure resting energy expenditure rather than predict it, but measurement also has limitations.
Which number should I use?
Use TDEE (maintenance) to plan what you eat, and BMR to understand your base. The free Get Your BMR quiz turns both into a daily target and a protein range.
