BMR Calculator
Your body burns calories even doing nothing. Find your Basal Metabolic Rate — the foundation of every calorie plan.
Find your basal metabolic rate
This is what you'd burn lying still all day. Real daily burn (TDEE) is always higher — see below.
What Is BMR?
Your Basal Metabolic Rate is the number of calories your body burns in 24 hours doing absolutely nothing — lying still, awake, in a comfortable room, after fasting. It powers the non-negotiables: breathing, blood circulation, brain function, body heat, cell repair.
BMR is the biggest slice of your daily calorie burn, typically 60–70% of the total. That's why it matters for weight planning: it sets the floor. You can't sustainably eat below your BMR for long without your body fighting back — fatigue, muscle loss, hormonal disruption.
The Mifflin-St Jeor Formula Explained
This calculator uses the Mifflin-St Jeor equation (1990), developed by comparing predicted values against actual metabolic measurements — and still the most accurate widely-used BMR formula for healthy adults:
Notice what the formula rewards: weight and height raise BMR (bigger bodies cost more to run), while age lowers it (about 5 kcal per year — the slow metabolic creep behind middle-age weight gain). The ±161/5 sex difference reflects average differences in muscle mass.
Worked Example
Profile: man, 30 years, 180 cm, 80 kg
Step 1: 10 × 80 = 800
Step 2: 6.25 × 180 = 1,125
Step 3: 5 × 30 = 150 (subtracted)
Step 4: add 5 for men
Result: 800 + 1,125 − 150 + 5 = 1,780 kcal/day — what his body burns at complete rest, or about 12,460 kcal per week.
BMR vs TDEE: What's the Difference?
BMR is your idle burn — the engine running in the driveway. TDEE (Total Daily Energy Expenditure) is the full day's fuel including everything you do: walking, working, exercising, even digesting food. TDEE is always higher than BMR.
The link between them is simple: TDEE = BMR × activity factor (1.2 for sedentary up to 1.9 for athletes). Our example man has a BMR of 1,780; if he's moderately active, his TDEE is about 2,759 kcal. For diet planning, TDEE is the number that matters — BMR is just the starting point. Try our TDEE Calculator to get yours.
How to Boost Your BMR
You can't change your age or height, but BMR isn't fixed:
- Build muscle. Muscle burns roughly 3× more calories at rest than fat. Adding 2 kg of muscle can raise BMR by ~30–50 kcal/day — small per day, meaningful per year.
- Don't crash diet. Aggressive deficits (1,000+ kcal) trigger metabolic adaptation — your body burns less to protect itself. Moderate deficits preserve BMR far better.
- Sleep 7–9 hours. Chronic sleep loss disrupts the hormones regulating metabolism and hunger.
- Eat enough protein. It has the highest thermic effect (~20–30% of its calories burned in digestion) and protects muscle during weight loss.
- Stay active daily. Exercise doesn't just burn calories during the workout — regular training, especially strength training, keeps resting metabolism higher.
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Save a number once — like your rent or hourly rate — then just type its name instead of the number, in any calculator here. You can also type formulas like 5000 * 1.1 right into any box.
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Frequently Asked Questions
What is a good BMR?
There is no universal "good" — BMR scales with size. Typical values run about 1,400–1,800 kcal/day for women and 1,600–2,000 for men. What matters is that your BMR reflects your body: a higher BMR at the same weight usually means more muscle, which is a good sign.
How is BMR calculated?
This calculator uses the Mifflin-St Jeor equation: for men, 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women, the same minus 161 instead of plus 5. It was validated against measured metabolic rates and remains the most accurate widely-used formula.
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest; TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor covering everything you do all day. TDEE is always higher — for a moderately active person, roughly 1.55× BMR — and it is the number that matters for diet planning.
Can I increase my BMR?
Yes, modestly. Building muscle raises it (muscle burns more at rest than fat), strength training and daily activity keep it higher, and adequate sleep and protein help. Crash dieting does the opposite — large deficits trigger metabolic adaptation that lowers BMR.
Is BMR the same as metabolism?
BMR is the largest part of your metabolism — about 60–70% of daily calorie burn — but not the whole thing. Your full metabolism (TDEE) also includes daily movement, exercise, and the energy cost of digesting food.