Use the most accurate Basal Metabolic Rate (BMR) Calculator to estimate the number of calories your body burns at rest. This is the foundation for creating any effective nutrition or weight-loss plan.
Best BMR Calculator
Your Estimated BMR is:
— Kcal/day —Best BMR Calculator Formula: Mifflin-St Jeor Equation
For Men: $$ \text{BMR} = 10 \times \text{Weight}(\text{kg}) + 6.25 \times \text{Height}(\text{cm}) – 5 \times \text{Age}(\text{y}) + 5 $$
For Women: $$ \text{BMR} = 10 \times \text{Weight}(\text{kg}) + 6.25 \times \text{Height}(\text{cm}) – 5 \times \text{Age}(\text{y}) – 161 $$
Formula Source & Authority: National Institutes of Health (NIH) Study, ACSM Journal Research
Variables Used in the Calculation
- Gender: Used to select the appropriate constant in the formula (+5 for men, -161 for women).
- Age (Years): Metabolism naturally slows with age, decreasing the BMR value.
- Weight (kg/lbs): A higher body mass requires more energy to maintain, increasing BMR.
- Height (cm/ft/in): Taller individuals typically have a higher BMR due to greater surface area and tissue mass.
What is Basal Metabolic Rate (BMR)?
The Basal Metabolic Rate (BMR) represents the total number of calories your body needs to perform essential, life-sustaining functions while at rest. These functions include breathing, circulating blood, regulating body temperature, cell production, and maintaining brain and nerve function.
BMR is the single largest component of your total energy expenditure, accounting for 60-75% of the calories you burn daily. It does not account for calories burned during physical activity or through the thermic effect of food (digestion).
Understanding your BMR is crucial for setting effective fitness and weight management goals. If you want to lose weight, you must consume fewer calories than your Total Daily Energy Expenditure (TDEE), which is BMR multiplied by an activity factor.
How to Calculate BMR (Example)
Let’s calculate the BMR for a 30-year-old male who is 175 cm tall and weighs 75 kg using the Mifflin-St Jeor formula.
- Identify the Gender Formula: Since the individual is male, we use: $$\text{BMR} = (10 \times \text{Weight}) + (6.25 \times \text{Height}) – (5 \times \text{Age}) + 5$$
- Plug in the Values: Substitute the given values into the formula: $$\text{BMR} = (10 \times 75) + (6.25 \times 175) – (5 \times 30) + 5$$
- Calculate the Components:
- $10 \times 75 = 750$
- $6.25 \times 175 = 1093.75$
- $5 \times 30 = 150$
- Sum the Results: $$\text{BMR} = 750 + 1093.75 – 150 + 5$$
- Final BMR: $$\text{BMR} = 1698.75 \text{ Calories/day}$$
Frequently Asked Questions (FAQ)
BMR (Basal Metabolic Rate) is measured under very restrictive conditions, such as a state of complete rest in a neutrally temperate environment, and requires a 12-hour fast. RMR (Resting Metabolic Rate) is measured under less strict, more practical conditions (usually after a 3-4 hour fast). The Mifflin-St Jeor equation technically estimates RMR, but the terms are often used interchangeably in general contexts.
You can increase your BMR primarily by increasing your lean muscle mass through strength training. Muscle tissue requires more energy to maintain than fat tissue, increasing the number of calories burned at rest.
You should recalculate your BMR whenever there is a significant change in your body metrics, such as a weight loss or gain of 5 kg (10 lbs) or more, or if you significantly change your training regimen.
The Mifflin-St Jeor equation used in this calculator is widely considered the most accurate prediction formula available. However, it is still an estimation. The only way to get a truly precise measurement is through a clinical test using indirect calorimetry.