BMR Calculator

Your Body Measurements

BMR is the number of calories your body burns at complete rest. Enter your details below for a personalized calculation.

Gender

Age
years

Weight kg or lbs

Height cm or ft in

Activity Level

About This BMR Calculator

This BMR Calculator uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate — the number of calories your body burns at complete rest. It also calculates your Total Daily Energy Expenditure (TDEE) based on your activity level, helping you understand your daily calorie needs for weight maintenance, loss, or gain.

How to Use

1. Select Gender — Choose Male or Female for accurate formula selection.

2. Enter Your Age — Input your age in years (15-120).

3. Enter Your Weight — Use kilograms or pounds. The calculator automatically syncs between units.

4. Enter Your Height — Use centimeters or feet/inches. Values sync automatically.

5. Select Activity Level — Choose the option that best matches your daily exercise routine.

6. Click Calculate — Press the "Calculate BMR" button to see your results and personalized calorie recommendations.

How It Works & Formula

BMR is calculated using the Mifflin-St Jeor equation, widely considered the most accurate formula for estimating basal metabolic rate in healthy adults.

For Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(y) + 5

For Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(y) − 161

Where:
• Weight = Body weight in kilograms.
• Height = Body height in centimeters.
• Age = Age in years.
• BMR = Basal Metabolic Rate in calories per day.

TDEE = BMR × Activity Factor

Activity Factors:
• Sedentary (1.2) – Little or no exercise
• Lightly active (1.375) – Light exercise 1-3 days/week
• Moderately active (1.55) – Moderate exercise 3-5 days/week
• Very active (1.725) – Hard exercise 6-7 days/week
• Super active (1.9) – Physical job + intense training

Mathematical Expression

BMR = 10W + 6.25H − 5A + S

TDEE = BMR × AF

Where S = +5 for males, -161 for females; AF = Activity Factor.

Real-Life Example

Example: A 30-year-old female weighing 65 kg (143 lbs) and 165 cm (5'5") tall, with a lightly active lifestyle.

BMR = (10 × 65) + (6.25 × 165) − (5 × 30) − 161
BMR = 650 + 1031.25 − 150 − 161
BMR = 1,370 calories/day
TDEE = 1,370 × 1.375 = 1,884 calories/day

This person burns about 1,370 calories at complete rest and needs approximately 1,884 calories daily to maintain their current weight with light activity.

Tip: To lose 1 lb per week, subtract 500 calories from TDEE (about 1,384 calories/day). To gain weight, add 500 calories.

Activity Level Reference Table

Use this table to understand how different activity levels affect your daily calorie needs.

Activity Level	Multiplier	Description	Example (BMR = 1,500)
Sedentary	1.2	Little or no exercise, desk job	1,800 cal/day
Lightly Active	1.375	Light exercise 1-3 days/week	2,062 cal/day
Moderately Active	1.55	Moderate exercise 3-5 days/week	2,325 cal/day
Very Active	1.725	Hard exercise 6-7 days/week	2,587 cal/day
Super Active	1.9	Physical job + intense training	2,850 cal/day

TDEE (Total Daily Energy Expenditure) = BMR × Activity Multiplier

Frequently Asked Questions

What is BMR and why is it important? +

BMR (Basal Metabolic Rate) is the number of calories your body needs to perform basic life-sustaining functions like breathing, circulation, and cell production. Knowing your BMR helps you understand your minimum calorie needs and serves as the foundation for calculating total daily energy expenditure.

What is the difference between BMR and TDEE? +

BMR is calories burned at complete rest (like sleeping). TDEE (Total Daily Energy Expenditure) includes all activity — walking, exercise, digestion, and daily movement. TDEE = BMR × Activity Factor and represents your true daily calorie needs for weight maintenance.

Is the Mifflin-St Jeor formula accurate? +

Yes, the Mifflin-St Jeor equation is considered the most accurate BMR formula for healthy adults. Studies show it's within 10-15% of true metabolic rate for most people. However, individual variations due to genetics, muscle mass, and medical conditions can affect actual BMR.

How much weight can I lose per week? +

A safe and sustainable rate is 0.5-1 kg (1-2 lbs) per week. To lose 1 lb per week, create a 500-calorie daily deficit (eat 500 calories less than your TDEE). Rapid weight loss can lead to muscle loss, nutritional deficiencies, and metabolic slowdown.

Does muscle mass affect BMR? +

Yes, significantly. Muscle tissue burns more calories at rest than fat tissue. People with higher muscle mass have higher BMR, which is why strength training is recommended for weight management. This BMR calculator provides estimates for average body composition.

How often should I recalculate my BMR? +

Recalculate whenever your weight changes significantly (5-10 lbs), age (yearly), or after major lifestyle changes. As you lose or gain weight, your BMR changes, so updating your numbers helps maintain accurate calorie targets.

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Understanding BMR

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and organs functioning.

Mifflin-St Jeor Formula

For men: BMR = 10×weight + 6.25×height − 5×age + 5
For women: BMR = 10×weight + 6.25×height − 5×age − 161

TDEE Explained

Total Daily Energy Expenditure = BMR × Activity Factor. This is your true daily calorie need for weight maintenance.

Weight Management

To lose weight: Eat 250-500 calories below TDEE. To gain weight: Eat 250-500 calories above TDEE.