BMR Calculator: Discover Your Metabolic Baseline
How many calories does your body burn just staying alive?
Your Basal Metabolic Rate (BMR) is the number of calories your body requires to perform basic life-sustaining functions such as breathing, circulation, and cell production; while at complete rest. Understanding your BMR is the foundation of any successful weight management plan.
Calculate Your BMR – Calculator
Basal Metabolic Rate (Energy at rest)
Calculate your baseline energy
The Equations We Use To Calculate The BMR
Not all metabolisms are measured the same way. Our calculator provides results using the most respected scientific formulas in the health industry:
Mifflin-St Jeor Equation (The Modern Standard)
This is the most widely used formula in the US and Canada. It is highly accurate for the average modern lifestyle.
- Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (y) + 5
- Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (y) − 161
Katch-McArdle Formula (For Athletes)
If you have a lean physique or know your body fat percentage, this formula is superior because it focuses on Lean Body Mass (LBM).
- Formula: 370 + 21.6 × Lean Mass (kg)
Why Knowing Your BMR Matters
Your BMR accounts for about 60% to 75% of your total daily energy expenditure.
- Weight Loss: To lose weight safely, you should generally never eat fewer calories than your BMR suggests, as your body needs this energy to keep your organs functioning.
- Metabolic Health: As you age or lose weight, your BMR naturally decreases. Strength training (building muscle) is the most effective way to increase your BMR.
- Customized Nutrition: Knowing your baseline allows you to calculate your TDEE (Total Daily Energy Expenditure) by adding your physical activity level.
BMR Frequently Asked Questions
BMR (Basal Metabolic Rate) is measured under very restrictive conditions (usually after 8 hours of sleep and 12 hours of fasting). RMR (Resting Metabolic Rate) is less restrictive and is usually slightly higher than BMR. For most people, the terms are used interchangeably in daily tracking.
Yes! Muscle tissue is more metabolically active than fat tissue. By increasing your muscle mass through resistance training, you raise your BMR, meaning you burn more calories even while you sleep.
As we age, we naturally lose lean muscle mass (a process called sarcopenia) and our hormonal profiles change. This is why many people in the UK and North America find they “gain weight easier” as they get older despite eating the same amount of food.
Yes. During pregnancy, a woman’s BMR increases significantly to support the growth of the fetus and the increased workload on the heart and lungs.