BMR Calculator

Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using the accurate Mifflin-St Jeor equation. Find out how many calories you need per day for weight loss, maintenance, or muscle gain based on your activity level.

BMR (Basal Metabolic Rate): The number of calories your body burns at rest just to maintain vital functions like breathing, circulation, and cell production. This calculator uses the Mifflin-St Jeor equation, the most accurate formula.

How It Works

1. Select Gender and Units

Choose your gender (male/female) as metabolic rates differ between genders, and select between imperial or metric units for measurements.

2. Enter Your Details

Input your age, current weight, and height. The calculator uses the Mifflin-St Jeor equation, the most accurate BMR formula available.

3. View Your BMR

Get your Basal Metabolic Rate - the number of calories your body burns at complete rest just to maintain vital functions.

4. Choose Activity Level

See your TDEE (Total Daily Energy Expenditure) for different activity levels, from sedentary to extra active. This is how many calories you actually need per day.

Examples

Example 1: Male - Moderate Activity

Gender: Male Age: 30 years Weight: 180 lbs Height: 5 feet 10 inches Results: BMR: 1,847 calories/day Moderate Activity TDEE: 2,863 calories/day To lose 1 lb/week: Eat 2,363 calories/day (500 calorie deficit) To maintain: Eat 2,863 calories/day To gain 1 lb/week: Eat 3,363 calories/day (500 calorie surplus)

Example 2: Female - Light Activity

Gender: Female Age: 25 years Weight: 140 lbs Height: 5 feet 5 inches Results: BMR: 1,424 calories/day Light Activity TDEE: 1,958 calories/day To lose 1 lb/week: Eat 1,458 calories/day To maintain: Eat 1,958 calories/day To gain 1 lb/week: Eat 2,458 calories/day

Frequently Asked Questions

What is BMR and why does it matter?

BMR (Basal Metabolic Rate) is the number of calories your body needs to perform basic life-sustaining functions - breathing, circulation, cell production, and nutrient processing. It represents 60-75% of your total daily calorie burn. Understanding your BMR helps you determine appropriate calorie intake for weight loss, maintenance, or gain.

What is the difference between BMR and TDEE?

BMR is your calorie burn at complete rest. TDEE (Total Daily Energy Expenditure) is your total daily calorie burn including all activities - exercise, work, daily movement, and digestion. TDEE = BMR × Activity Multiplier. For example, if your BMR is 1,500 and you are moderately active, your TDEE is 1,500 × 1.55 = 2,325 calories.

Which activity level should I choose?

Sedentary: Office job, little exercise. Light: Exercise 1-3 days/week, mostly sitting. Moderate: Exercise 3-5 days/week, some standing/walking. Very Active: Exercise 6-7 days/week or physical job. Extra Active: Athlete training or very physical job. Most people are sedentary or lightly active - be honest to avoid overestimating calorie needs.

How accurate is this calculator?

This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate BMR formula for the general population. However, individual metabolism varies by ±10-15% based on genetics, muscle mass, hormones, and other factors. Use this as a starting point and adjust based on real-world results over 2-4 weeks.

Can I eat below my BMR to lose weight faster?

No, eating significantly below your BMR for extended periods is not recommended. This can slow your metabolism, cause muscle loss, hormonal issues, fatigue, and nutrient deficiencies. For healthy weight loss, eat 500 calories below your TDEE (not BMR). This creates a safe deficit while ensuring your body gets enough energy for vital functions.