BMR is the number of calories your body needs to maintain basic life-sustaining functions while at complete rest — breathing, circulation, cell production, nutrient processing, and temperature regulation. It represents 60–75% of your total daily calorie expenditure.
Think of BMR as the energy your body would burn if you stayed in bed all day without moving. It is the minimum number of calories needed to keep you alive.
BMR vs TDEE — What's the Difference?
BMR (Basal Metabolic Rate): Calories burned at complete rest — your body's minimum requirement
TDEE (Total Daily Energy Expenditure): BMR + calories burned through all physical activity and digestion. This is your actual daily calorie need.
Rule of thumb: TDEE is typically 1.2x to 1.9x your BMR depending on activity level
Mifflin-St Jeor Formula (Used in This Calculator)
This calculator uses the Mifflin-St Jeor equation, published in 1990 and validated as the most accurate BMR formula for most people:
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Studies show this formula is accurate within 10% for 82% of people — making it the gold standard for BMR estimation.
What Affects Your BMR?
Muscle mass: Muscle burns 3x more calories than fat at rest — more muscle = higher BMR
Age: BMR decreases by approximately 2% per decade after age 20
Gender: Men typically have higher BMR due to greater muscle mass
Body size: Taller, heavier people burn more calories at rest
Genetics: Some people naturally have faster or slower metabolisms
Create a deficit: Eat 300–500 calories below TDEE for sustainable weight loss of 0.3–0.5 kg/week
Never go below BMR: Eating fewer calories than your BMR causes muscle loss and metabolic slowdown
Track progress: Recalculate every 4–6 weeks as weight changes
Combine with exercise: Burning calories through exercise while eating at a deficit is more effective than diet alone
How to Increase Your BMR Naturally
Build muscle: Strength training 3x/week progressively builds muscle that raises resting metabolism
Eat enough protein: High protein intake has a thermic effect — digesting protein burns 20–30% of its calories
Never crash diet: Very low calorie diets suppress BMR by up to 20–25% — the yo-yo effect
Stay hydrated: Even mild dehydration slows metabolism
Get enough sleep: Sleep deprivation reduces metabolic rate and increases hunger hormones
Drink green tea or coffee: Caffeine temporarily raises metabolism by 3–11%
❓ Frequently Asked Questions
Q: What is a normal BMR for Indians?
A: Average BMR for Indian men is approximately 1,400–1,700 kcal/day and for Indian women 1,200–1,500 kcal/day, depending on age, height, and weight. Indians generally have a slightly lower muscle mass compared to Western populations at the same BMI, which can mean a slightly lower BMR. However, the Mifflin-St Jeor formula is still accurate for Indian individuals.
Q: Should I eat at my BMR or TDEE?
A: Always eat at or above your BMR — never below it. Your TDEE is the right baseline. To lose weight, eat 300–500 calories below your TDEE. Eating below BMR starves your body of essential nutrients and causes muscle loss, metabolic adaptation, and nutritional deficiencies.
Q: Why is my BMR different from online calculators?
A: Different calculators use different formulas — Harris-Benedict, Mifflin-St Jeor, Katch-McArdle. The Mifflin-St Jeor formula (used here) is the most validated and accurate for the general population. Differences of 50–150 kcal between calculators are normal and within the margin of estimation error.
Q: How accurate is BMR calculation?
A: The Mifflin-St Jeor equation is accurate within ±10% for most people. This means if your calculated BMR is 1,500 kcal, your true BMR is likely between 1,350–1,650 kcal. For precise measurement, indirect calorimetry (a clinical test) is needed. For practical purposes, use the calculated BMR as a starting point and adjust based on actual results over 2–4 weeks.
Q: Does BMR decrease with age?
A: Yes — BMR decreases by approximately 1–2% per decade after age 20, primarily due to loss of muscle mass (sarcopenia). A 50-year-old typically has a BMR 10–15% lower than when they were 20. Regular strength training can significantly slow or even reverse this decline by maintaining or building muscle mass.
⚠️ Disclaimer
This BMR calculator provides estimates based on standard formulas. Individual metabolism varies significantly. For medical conditions affecting metabolism (thyroid disorders, diabetes, etc.), consult a healthcare professional or registered dietitian for personalised calorie targets.