BMR Calculator
Find your resting metabolic rate and calories by activity level.
Age
Height
Weight
Basal Metabolic Rate
1,628 kcal
Calories your body burns at complete rest, per day
1,628 kcal
Calories burned per day by activity
Sedentary
Little or no exercise
1,953 kcal
Light
Exercise 1–3 days/week
2,238 kcal
Moderate
Exercise 3–5 days/week
2,523 kcal
Active
Exercise 6–7 days/week
2,807 kcal
Very Active
Physical job or 2x/day training
3,092 kcal
How this calculator works
This uses the Mifflin-St Jeor equation, published in 1990 and now the formula most dietitians treat as the most accurate for the general population: for men, BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women, the same calculation minus 161. It replaced the older 1919 Harris-Benedict equation, which tends to overestimate BMR for most people by a noticeable margin.
Worked example
A 28-year-old man who is 170cm tall and weighs 70kg has a BMR of (10 × 70) + (6.25 × 170) − (5 × 28) + 5 = 700 + 1062.5 − 140 + 5 = 1,627.5 kcal/day. That's the energy his body burns lying in bed all day — before walking, working, or exercising adds anything on top.
BMR vs. TDEE
BMR alone isn't a useful number for planning your diet — almost nobody spends 24 hours completely motionless. The activity table above multiplies BMR by a factor for how much you actually move day-to-day, giving your Total Daily Energy Expenditure (TDEE) at each level. TDEE, not BMR, is the number to use as a baseline for a calorie deficit or surplus.
How accurate is this estimate?
Even the best predictive equations are estimates from population averages — individual metabolic rate can vary by roughly 10–15% either side of the prediction depending on genetics, muscle mass, and hormonal factors that a formula using only age, height and weight can't capture. Muscle burns more calories at rest than fat does, so two people with the same stats but different body composition can have meaningfully different real BMRs. Treat this as a starting point to adjust from based on how your actual weight trends over a few weeks, not a fixed number.
Turning this into a calorie target
Once you have your TDEE at your activity level, the Calorie Calculator applies a deficit or surplus on top of it for weight loss, maintenance or gain, and the Protein Intake Calculator can help set a protein target to go with it.
Frequently Asked Questions
What is BMR?
Basal Metabolic Rate is the number of calories your body burns at complete rest just to keep you alive — breathing, circulation, cell repair — before any activity is added on top.
Which formula does this calculator use?
It uses the Mifflin-St Jeor equation, generally considered the most accurate widely-used formula for estimating BMR from weight, height, age and sex.
How is BMR different from TDEE?
BMR is calories burned at total rest. Total Daily Energy Expenditure (TDEE) adds your activity level on top of BMR — it's the number that actually reflects how many calories you burn in a normal day, and the one to use for weight loss or gain targets.
How accurate is a BMR formula?
It's a population-average estimate, typically within about 10-15% of your true resting metabolic rate. Muscle mass, genetics and hormones all affect real BMR in ways a formula using only age, height and weight can't capture — use it as a starting point, then adjust based on how your actual weight trends.
Why does this calculator use Mifflin-St Jeor instead of Harris-Benedict?
Harris-Benedict dates from 1919 and tends to overestimate BMR for most people. Mifflin-St Jeor, published in 1990 from more modern data, is generally regarded as more accurate for the general population and is the formula most dietitians default to today.
This tool provides general estimates for informational purposes only and isn't a substitute for professional medical advice. Consult a doctor or qualified healthcare provider before making decisions about your health.