BMR (Basal Metabolic Rate) Calculator

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body needs to accomplish its most basic (basal) life-sustaining functions, such as breathing, circulation, nutrient processing, and cell production. BMR is the minimum amount of energy needed to keep your body functioning at rest.

Your BMR is influenced by several factors including:

• Age: BMR decreases as you age
• Gender: Men generally have a higher BMR than women
• Body composition: More muscle mass increases BMR
• Body size: Larger bodies have higher BMRs
• Genetics: Some people naturally have higher or lower BMRs
• Hormones: Thyroid issues can affect BMR
• Environmental temperature: Extreme temperatures can increase BMR

BMR Calculation Formulas

This calculator offers three different formulas to estimate your BMR:

1. Mifflin-St Jeor Equation (Recommended)

This is considered the most accurate formula for most people:

• For men: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
• For women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

2. Harris-Benedict Equation

This is an older formula but still widely used:

• For men: BMR = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) – (6.75 × age in years)
• For women: BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) – (4.676 × age in years)

3. Katch-McArdle Formula

This formula takes into account lean body mass, which can be more accurate for athletic individuals:

• BMR = 370 + (21.6 × Lean Body Mass in kg)
• Where Lean Body Mass = Weight in kg × (1 – Body Fat % / 100)

Activity Levels Explained

To estimate your total daily calorie needs, your BMR is multiplied by an activity factor:

Activity Level	Description	Factor
Sedentary	Little or no exercise, desk job	BMR × 1.2
Lightly active	Light exercise or sports 1-3 days a week	BMR × 1.375
Moderately active	Moderate exercise or sports 3-5 days a week	BMR × 1.55
Very active	Hard exercise or sports 6-7 days a week	BMR × 1.725
Extra active	Very hard exercise, physical job, or training twice a day	BMR × 1.9

Using Your BMR Results

Once you know your BMR and total daily calorie needs, you can use this information to:

• Weight maintenance: Consume the same number of calories as your daily calorie needs
• Weight loss: Consume fewer calories than your daily calorie needs (typically 500 calories less per day to lose 1 pound per week)
• Weight gain: Consume more calories than your daily calorie needs (typically 500 calories more per day to gain 1 pound per week)

Remember that BMR calculations are estimates. Individual factors like genetics, medical conditions, and specific body composition can affect your actual calorie needs. Always consult with a healthcare professional before making significant changes to your diet or exercise routine.