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BMR Calculator

Health

Calculate your Basal Metabolic Rate using the Mifflin-St Jeor equation. Know your minimum daily calorie need to maintain basic body functions at rest.

Reviewed by the thecalcu.com team · Last updated July 21, 2026

Gender
Age
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1580
Weight
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30200
Height
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100250

BMR (kcal/day)

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BMR (kJ/day)
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Calories per Hour
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What is a BMR?

A BMR Calculator computes your Basal Metabolic Rate, the number of calories your body burns at complete rest just to sustain essential life functions: heartbeat, breathing, body temperature regulation, cell repair, and brain activity. BMR represents the floor of your calorie needs; you would burn this many calories even if you did nothing but lie still all day.

This calculator uses the Mifflin-St Jeor equation, the most accurate and widely used formula for estimating BMR in healthy adults. It was developed in 1990 and validated across diverse populations, making it more reliable than the older Harris-Benedict formula that most calculators still use.

For Indian users, BMR is the essential starting point for:

  • Weight loss planning, knowing your calorie floor prevents under-eating
  • Muscle gain diets, understanding calorie surplus targets
  • Health monitoring, tracking metabolic changes with age or after illness

BMR is not the same as your full daily calorie need, that requires accounting for your physical activity level. Use this result with the TDEE Calculator to find your activity-adjusted daily requirement.

Why Use a BMR Calculator?

Most people trying to lose or gain weight pick an arbitrary calorie target, 1200, 1500, 2000 kcal/day, without knowing whether it suits their specific body. BMR anchors all calorie decisions in physiology.

For a 28-year-old woman in Mumbai who is 163 cm tall and weighs 60 kg:

  • BMR ≈ 1,394 kcal/day
  • If she eats 1,200 kcal/day to "diet", she's eating below her BMR
  • This triggers metabolic slowdown and muscle loss, counterproductive for long-term weight management

Knowing your BMR means you can set a calorie deficit (for loss) or surplus (for gain) relative to a real physiological baseline, not an arbitrary number.

Who Should Use This Calculator?

People trying to lose weight who want to understand the minimum calorie floor before setting a deficit. Eating below BMR for extended periods leads to muscle loss and metabolic adaptation, the BMR shows where the danger zone begins.

Gym-goers and athletes who need to calculate their protein requirements and calorie surplus for muscle building. Muscle gain requires eating above TDEE, which is anchored in BMR.

Dietitians and nutritionists in India who need a quick population-standard BMR estimate for clients before personalising meal plans. Pair with the Body Fat Calculator for lean mass-adjusted estimates.

People with thyroid conditions or metabolic disorders who want a baseline estimate to understand how far their actual measured metabolic rate deviates from the population norm.

Students and professionals studying nutrition, exercise science, and allied health who need a reliable reference for the Mifflin-St Jeor calculation.

What Does the BMR Result Tell You?

BMR (kcal/day) is your daily calorie burn at rest. A typical Indian adult male (30 years, 70 kg, 170 cm) has a BMR of approximately 1,695 kcal/day; a typical Indian adult female (30 years, 55 kg, 160 cm) has a BMR of approximately 1,334 kcal/day.

BMR (kJ/day) is the same value in kilojoules (1 kcal = 4.184 kJ). Some dietitians and international food labels use kJ.

Calories per hour (BMR ÷ 24), shows how fast your body burns calories at rest. For reference, 60–70 kcal/hour is typical for a resting adult.

Use BMR as the input to multiply by an activity factor:

  • Sedentary (desk job, no exercise): BMR × 1.2
  • Light activity (1–3 days/week): BMR × 1.375
  • Moderate activity (3–5 days/week): BMR × 1.55
  • Very active (6–7 days/week): BMR × 1.725

How to use this BMR calculator

  1. Select your Gender, Male or Female. This changes the constant in the Mifflin formula (+5 for men, −161 for women).
  2. Enter your Age in years using the slider or input field.
  3. Enter your Weight in kilograms. Use a digital scale for accuracy; small errors in weight significantly affect the result.
  4. Enter your Height in centimetres. Convert from feet: multiply feet by 30.48 and add inches × 2.54.
  5. The BMR result appears instantly in kcal/day, this is your metabolic floor.
  6. Note the kJ/day result if you're referencing international nutrition guidelines that use kilojoules.
  7. Take your BMR result to the TDEE Calculator and select your activity level to find your full daily calorie requirement.

Formula & Methodology

Mifflin-St Jeor Equation (1990):

Men:   BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age_years) + 5 Women: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age_years) − 161

Worked example, 32-year-old male in Hyderabad, 75 kg, 175 cm:
BMR = (10 × 75) + (6.25 × 175) − (5 × 32) + 5     = 750 + 1093.75 − 160 + 5     = 1,688.75 kcal/day ≈ 1,689 kcal/day     = 7,067 kJ/day     = 70.4 kcal/hour

BMR reference table for Indian adults:

| Profile | BMR (approx.) |
|---|---|
| Woman, 25 yrs, 55 kg, 160 cm | 1,334 kcal/day |
| Woman, 40 yrs, 65 kg, 162 cm | 1,417 kcal/day |
| Man, 25 yrs, 65 kg, 170 cm | 1,659 kcal/day |
| Man, 40 yrs, 80 kg, 175 cm | 1,745 kcal/day |
| Man, 55 yrs, 75 kg, 172 cm | 1,600 kcal/day |

BMR in kJ = BMR in kcal × 4.184. All values are estimates; individual metabolic rates vary by ±10%.

Frequently Asked Questions

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest, the minimum energy required to keep your heart beating, lungs breathing, brain functioning, and organs running. It accounts for roughly 60–75% of your total daily calorie expenditure. BMR is the starting point for all calorie and diet calculations.
This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate general-purpose BMR formula for the adult population. Published in 1990, it has been validated across diverse populations and is preferred by most dietitians and health organisations over the older Harris-Benedict equation. The formulas are: 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.
BMR is your calorie burn at absolute rest, if you lay still all day without eating or moving, you would burn exactly your BMR. TDEE (Total Daily Energy Expenditure) is your actual daily calorie burn, which includes physical activity on top of BMR. TDEE = BMR × Activity Multiplier. For most active adults, TDEE is 1.4–1.9 × their BMR. Use the TDEE Calculator to compute your full daily calorie need.
For Indian adults, BMR typically ranges from 1200–1600 kcal/day for women and 1400–1900 kcal/day for men, depending on height, weight, and age. India's National Institute of Nutrition (NIN) reference body weights (55 kg for women, 65 kg for men) correspond to BMR values around 1350 kcal/day (women) and 1600 kcal/day (men). Individual values vary widely based on body composition.
Yes, BMR decreases with age, primarily because muscle mass tends to decline with age (a process called sarcopenia) while body fat percentage increases. Muscle tissue is more metabolically active than fat, so less muscle means a lower BMR. Research suggests BMR decreases by approximately 1–2% per decade after age 30. This is one reason why gradual weight gain is common in middle age even with similar eating habits.
Men typically have a higher BMR than women of the same age, height, and weight, usually by 5–10%. This is primarily because men generally have a higher percentage of lean muscle mass and lower body fat percentage than women. The Mifflin-St Jeor equation accounts for this with the +5 constant for men and −161 constant for women. Hormonal differences, particularly testosterone's muscle-building effects, also contribute.
BMR alone is not enough to plan a diet, you need your TDEE (BMR × activity level). Once you know your TDEE, create a calorie deficit: reducing intake by 500 kcal/day below TDEE typically results in approximately 0.5 kg of weight loss per week. Never eat below your BMR for sustained periods; doing so triggers metabolic adaptation where your body reduces its BMR to conserve energy. Use the Calorie Calculator for diet planning.
Select your gender, then enter your age in years, weight in kilograms, and height in centimetres. The BMR updates instantly. The result is shown in kcal/day (kilocalories per day), the standard unit used on food labels in India. Use this BMR as the input to the TDEE Calculator to find your activity-adjusted daily calorie requirement.
The Mifflin-St Jeor equation estimates BMR from age, gender, height, and weight. It does not account for: thyroid function (hypothyroidism significantly lowers BMR), lean body mass vs. fat mass (a muscular person has a higher BMR than the formula predicts), chronic illness, and medication effects. For clinical purposes, indirect calorimetry (metabolic cart testing) is used for precise measurement. The calculator gives a statistically accurate population estimate.
BMR (Basal Metabolic Rate) and RMR (Resting Metabolic Rate) are often used interchangeably, but technically differ in measurement conditions. BMR is measured after 8+ hours of sleep, 12+ hours fasting, in a thermoneutral environment at complete physical rest. RMR is measured simply at rest, without the strict fasting and sleep requirements, making it slightly higher (2–3%) than BMR. In practice, most online calculators compute RMR while calling it BMR.
The Mifflin-St Jeor equation predicts BMR within ±10% for most adults. In a 2005 review, it was accurate within 10% for 82% of non-obese and 70% of obese individuals. For the average Indian adult, this means the result could be 130–160 kcal/day higher or lower than your true BMR. This level of accuracy is sufficient for practical diet planning, track your actual weight response over 2–4 weeks and adjust calories accordingly.
Every kilogram of body weight adds approximately 10 kcal/day to your BMR (from the Mifflin formula). However, the type of weight matters: 1 kg of muscle has higher metabolic activity than 1 kg of fat. Given that Indian adults have higher average body fat percentage at the same BMI compared to Caucasian populations (a phenomenon well-documented in research), the Mifflin formula may slightly overestimate BMR for some Indian individuals. For weight management, pairing BMR with body fat percentage data from the Body Fat Calculator gives a more accurate picture.
Also known as
basal metabolic rateBMRresting metabolic ratecalorie burn at restBMR formula