BMR Calculator
Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — just to keep you alive: breathing, circulation, cell repair. It forms the floor of your daily calorie needs.
Mifflin-St Jeor Formula
Women: BMR = 10W + 6.25H − 5A − 161
Where W = weight in kg, H = height in cm, A = age in years.
BMR vs TDEE
TDEE (Total Daily Energy Expenditure) is your actual daily calorie burn based on your activity. It's BMR multiplied by an activity factor. Eat at TDEE to maintain weight, below it to lose, above it to gain.
Using This for Weight Goals
- Lose weight — Eat ~500 kcal/day less than TDEE for ~0.5 kg/week loss
- Maintain — Eat at your TDEE
- Gain muscle — Eat ~300–500 kcal/day above TDEE with strength training
Frequently Asked Questions
Does BMR change with age?
Yes. BMR declines roughly 2–3% per decade after age 20, primarily due to loss of muscle mass. This is why staying active and preserving muscle becomes more important as you age.
Why is my TDEE different from fitness app estimates?
Activity multipliers are estimates. Actual TDEE varies based on non-exercise activity (fidgeting, walking around), metabolic adaptation, and individual variation. Track actual weight change over 2–3 weeks and adjust calories accordingly.