BMR (Basal Metabolic Rate) is the number of calories your body needs to maintain basic functions at complete rest — breathing, circulation, cell production, and temperature regulation.

Which BMR formula is most accurate?

The Mifflin-St Jeor equation (1990) is considered the most accurate for most people. This calculator uses that formula.

BMR Calculator - Basal Metabolic Rate Calculator

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BMR Calculator

Find your daily calorie needs at rest and with activity

Age?Your age in years. BMR decreases by about 1-2% per decade after age 20 as metabolism naturally slows.

yrs

Biological Sex?The BMR formula uses biological sex because males typically have more muscle mass, resulting in a higher metabolic rate.

Weight?Your current body weight. Use the same scale consistently for tracking over time.

Height?Your height. Taller people generally have a higher BMR since they have more body surface area to maintain.

Activity Level?Your typical daily activity level. Be honest — most people overestimate their activity. Choose "lightly active" if you exercise 1-3 times per week.

Basal Metabolic Rate (BMR)

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calories/day at complete rest

TDEE (with activity)

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To Lose Weight

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To Gain Weight

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What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body burns every day just to keep you alive — maintaining heartbeat, breathing, body temperature, and cellular repair — while you're completely at rest. It accounts for 60-75% of your total daily calorie burn.

Understanding your BMR helps you make informed decisions about nutrition and weight management. Eating significantly below your BMR for extended periods can actually slow metabolism and cause muscle loss, which is why extreme diets are counterproductive.

BMR Formula (Mifflin-St Jeor)

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

TDEE = BMR × Activity Multiplier

How to use this calculator

Select metric or imperial units
Enter your age, biological sex, weight, and height
Select your activity level (be honest — most people are "lightly active")
Click Calculate to see your BMR and TDEE
Use the calorie targets to plan your diet for weight loss, gain, or maintenance

📘 Example Scenarios

Scenario 1 — Neha wants to lose weight 🎯

Neha is a 28-year-old woman, 60 kg, 162 cm, works a desk job with light exercise (lightly active). Her BMR = ~1,390 kcal. Her TDEE = ~1,911 kcal. To lose 0.5 kg/week, she should eat about 1,411 kcal/day (500 calorie deficit). This is sustainable and prevents muscle loss.

Scenario 2 — Mike wants to build muscle 💪

Mike is a 25-year-old man, 75 kg, 178 cm, goes to the gym 4 days a week (moderately active). His BMR = ~1,840 kcal. His TDEE = ~2,852 kcal. To gain muscle, he should eat ~3,100 kcal/day (250-300 calorie surplus) with sufficient protein. More than this adds excess fat.

Frequently asked questions

BMR is the number of calories your body burns at complete rest to maintain vital functions. Think of it as the minimum fuel your engine needs to keep running.

No — eating below your BMR for extended periods can cause muscle loss, nutrient deficiencies, and metabolic adaptation (slowing metabolism). Create a deficit from your TDEE, not your BMR.

As we age, we tend to lose muscle mass (sarcopenia). Since muscle burns more calories than fat even at rest, less muscle means a lower BMR. Regular strength training helps preserve BMR.

BMR is calories burned at rest. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor — representing all calories burned in a day including exercise, walking, and daily tasks.

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