What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — just to keep your heart beating, your lungs moving, your brain thinking, and your cells repairing. It's the irreducible cost of being alive.
BMR makes up about 60–75% of total daily calorie burn for most adults. The remainder comes from physical activity and the small thermic effect of digesting food.
Knowing your BMR tells you the absolute floor of what your body needs. Eating below it for extended periods is unsustainable and counterproductive.
How the BMR calculator works
We use the Mifflin–St Jeor equation, the formula most clinicians and registered dietitians rely on. It estimates BMR from your weight, height, age, and sex.
For men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. For women: same, minus 161 instead of plus 5. The formula has been validated against indirect calorimetry within ±10% for most non-athletic adults.
If you want your total daily burn instead of just resting, see the TDEE calculator. If you want the calorie target for losing weight, see the calorie deficit calculator.
From BMR to a daily plan
BMR is a starting point, not a meal plan. To eat for a goal, you need to add activity (TDEE) and choose a direction — lose, maintain, or gain.
Click "Want a personalized meal plan?" above and we'll ask the two extra questions, calculate your daily target, and assemble a one-day plan — 3–4 meals, total within 10% of target, with portion sizes already scaled.
It's one plan, on us. If you want a fresh plan every day plus automatic tracking that learns your habits, that's what Nuvvoo does.
Want a new plan every day and automatic tracking?
Try Nuvvoo, the modern calorie tracker.
Frequently Asked Questions
Is BMR the same as TDEE?
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No. BMR is calories burned at rest. TDEE (Total Daily Energy Expenditure) adds the calories you burn through activity. TDEE = BMR × an activity multiplier (1.2 for sedentary up to 1.9 for very active).
Can I eat just my BMR to lose weight?
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It will produce weight loss but is rarely a good idea long-term. Eating at or below BMR makes most people miserable, drops energy and mood, and stalls progress as metabolism adapts. A modest deficit below your TDEE works better.
How accurate is Mifflin–St Jeor?
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Within ±10% for most non-athletic adults. It's less accurate for very lean or very muscular people — the formula doesn't see body composition, only total weight. If you have a lot of muscle, your real BMR is higher than the equation says.
Why does BMR drop as I age?
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Two main reasons: loss of lean mass (muscle is metabolically active tissue) and small downshifts in cell-level metabolic rate. The age term in Mifflin–St Jeor (−5 × age) approximates the first; you can blunt it with resistance training.
Should I always eat above my BMR?
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For most healthy adults trying to lose weight slowly, yes — stay above BMR and create the deficit from your TDEE, not your BMR. People in supervised medical programs sometimes eat below BMR temporarily, but that's not a self-managed strategy.
Related guides
TDEE Calculator
Calculate your total daily energy expenditure.
Calorie Deficit Calculator
Get your daily calorie target and a one-day plan in one go.
Food Diary for Weight Loss
Turn your target into a chat-based diary that doesn't feel like homework.
Stay Consistent Tracking
Tracking 80% imperfectly beats 30% perfectly — how to actually stick with it.