BMR Calculator
Estimate Basal Metabolic Rate — calories your body burns at rest.
Inputs
Allowed range: 1 to 120
Allowed range: 50 to 272
Allowed range: 10 to 600
Results
How it works
We use the Mifflin–St Jeor equation: men 10·kg + 6.25·cm − 5·age + 5; women 10·kg + 6.25·cm − 5·age − 161.
Complete guide
Your Basal Metabolic Rate (BMR) is the number of calories your body burns just keeping you alive — heart beating, lungs breathing, brain working — if you spent the entire day lying still. It's the foundation of any calorie-tracking plan because everything you do on top of resting only adds to it.
The Mifflin–St Jeor equation used here is currently the most accurate general-purpose BMR formula for adults, validated in numerous studies since 1990. It accounts for sex, age, height, and weight.
To estimate your real daily calorie needs (TDEE), multiply BMR by an activity factor: 1.2 for sedentary desk work, 1.375 for light exercise 1–3 days/week, 1.55 for moderate exercise 3–5 days/week, 1.725 for hard exercise 6–7 days/week.
For weight loss, eat roughly 300–500 calories below TDEE. For weight gain, eat 300–500 above. Extreme deficits backfire by lowering BMR over time.
Frequently asked questions
- Is BMR the same as calories burned per day?
- No. BMR is your resting baseline. Total daily energy expenditure (TDEE) is BMR multiplied by an activity factor and is what you actually burn.
- Why does BMR drop with age?
- Adults lose muscle mass and metabolically active tissue over time. Strength training is the most effective way to slow this decline.
- Can I trust my smartwatch's calorie estimate?
- Wearables can be off by 20–30%. Use the formula here as a sanity check against what your watch reports.
- Why are men's and women's formulas different?
- On average, men carry more lean muscle mass at a given height and weight, which raises resting energy expenditure.