Discover your estimated resting calorie burn and daily maintenance needs using the Mifflin-St Jeor equation and your activity level.
Results use the Mifflin-St Jeor equation.
How to use this tool, plus the formulas and logic behind the results.
The BMR Calculator estimates basal metabolic rate with the Mifflin-St Jeor equation and can scale that result by activity level to approximate maintenance calories.
Men: BMR = 10w + 6.25h − 5a + 5Women: BMR = 10w + 6.25h − 5a − 161Maintenance ≈ BMR × activity factorInputs are converted to metric kilograms and centimeters, then Mifflin-St Jeor is applied. The activity multiplier estimates total daily energy expenditure, not a clinical prescription.
How basal metabolism and daily energy use are estimated.
BMR stands for Basal Metabolic Rate. It represents the number of calories your body needs each day to perform essential functions such as breathing, circulating blood, regulating body temperature, and keeping your organs working while you're completely at rest. Your BMR does not include calories burned through exercise or everyday activities. Knowing your BMR can help you estimate your daily calorie needs when creating a weight loss, maintenance, or muscle gain plan.
Most online BMR calculators use scientifically developed equations such as the Mifflin-St Jeor Equation or the Harris-Benedict Equation. These formulas estimate your resting calorie needs based on factors including your age, sex, height, and weight. While they provide a good estimate for most healthy adults, they cannot account for every individual difference.
No. BMR and TDEE measure different things. BMR is the number of calories your body burns while completely at rest. TDEE, or Total Daily Energy Expenditure, includes your BMR plus the calories you burn through walking, exercising, working, and other daily activities. If you're planning your daily calorie intake, TDEE is generally the more useful number.
The Mifflin-St Jeor Equation is widely considered one of the most accurate methods for estimating BMR in healthy adults. Many nutrition professionals and fitness experts prefer it because it tends to provide reliable estimates across a wide range of body types. However, no formula can perfectly predict an individual's actual metabolism.
Your BMR provides a starting point for understanding how many calories your body needs every day. Whether your goal is losing weight, maintaining your current weight, or building muscle, knowing your BMR makes it easier to estimate your overall calorie requirements and create a nutrition plan that fits your goals.
Yes. BMR generally decreases as people get older. This happens because muscle mass often declines with age, while metabolic activity slows down. Staying physically active and maintaining muscle through strength training can help reduce this natural decline.
Yes. Muscle tissue burns more calories than fat tissue, even while you're resting. People with a higher percentage of lean muscle mass usually have a higher BMR. Building and maintaining muscle through regular resistance training can help support a healthier metabolism over time.
While genetics play a role in your metabolism, there are healthy ways to support a higher BMR. Building lean muscle, staying physically active, eating enough protein, getting quality sleep, and avoiding extreme calorie restriction can all help maintain a healthy metabolic rate.
Several factors can contribute to a lower BMR, including older age, smaller body size, lower muscle mass, or long periods of calorie restriction. Remember that BMR is only an estimate. Two people with similar measurements may still have different metabolic rates.
Yes, but BMR should only be used as a starting point. Weight loss depends on maintaining a calorie deficit, which is usually based on your TDEE rather than your BMR alone. Most people use their BMR to estimate TDEE and then adjust calorie intake according to their weight-loss goals.
This calculator provides an estimate based on widely accepted scientific formulas. For most healthy adults, the results are accurate enough for nutrition planning and fitness tracking. However, factors such as medical conditions, pregnancy, body composition, and genetics may affect your actual metabolic rate.
Yes. The same calculator can be used by both men and women, but the calculation formula takes biological sex into account because men and women generally have different body compositions and metabolic rates. Simply enter your information accurately to receive the appropriate estimate.
Most BMR calculators only require a few basic details: your age, biological sex, height, and current weight. Some calculators also allow you to choose between metric and imperial units, making it easy for users around the world.
In most cases, regularly eating fewer calories than your BMR is not recommended without medical supervision. Your BMR represents the energy your body needs to perform basic life functions. Consistently consuming too few calories may reduce energy levels, increase hunger, and make it harder to meet your nutritional needs.
You don't need to calculate your BMR every day. It's a good idea to recalculate whenever your weight changes significantly, your body composition changes, or every few months if you're actively working toward a fitness goal. Updating your numbers helps keep your calorie estimates more accurate.