BMR Calculator

BMR (Basal Metabolic Rate) is the amount of energy your body burns at complete rest to keep you alive—things like breathing, circulating blood, maintaining body temperature and basic organ function. It’s a way to measure your metabolism at rest and shows how many calories your body would burn even if you did nothing all day. It does not include walking, workouts, or daily activity, so think of it as your “coma calories” or the minimum energy cost of simply existing.

This free online BMR calculator uses the Mifflin-St Jeor formula, an advanced and research-supported equation for estimating resting metabolic rate. It provides an accurate, health-focused estimate by using your age, gender, height, and weight as inputs. The calculator automatically adjusts the equation based on gender so the result better reflects your body composition and metabolism.

• BMR (Basal Metabolic Rate) = calories your body burns at rest to maintain vital functions.
• TDEE (Total Daily Energy Expenditure) = BMR × activity level, so it includes all the energy you burn through movement, exercise, work, and everyday tasks.

You should use TDEE, not just BMR, when you calculate how many calories to eat for a specific fitness goal such as weight loss, maintenance, or muscle gain, because TDEE reflects your real-world energy burn and daily intake needs.

No. Eating at your BMR would usually be too low, because this number only reflects what your body needs at rest. For most users, BMR is the minimum to maintain basic functions, not an ideal daily calorie intake. For healthy weight management, it’s better to determine your TDEE with the calculator and then adjust your calories slightly below or above that, depending on your goal (fat loss, maintenance, or muscle gain).

1. Use the calculator to estimate your BMR.
2. Check the TDEE table below the main result and pick the activity level that best describes your lifestyle.
3. For weight loss, create a moderate deficit from your TDEE—often 500–750 calories per day.

This quick, interactive approach lets you customize your daily calorie intake to your fitness goal while keeping the process safe and sustainable. The idea is to optimize your energy balance, not starve your body.

Yes. As age increases, BMR usually goes down. Over time, people tend to lose muscle and experience hormonal changes, which slow the body’s metabolism and lower the resting calorie burn rate. That’s why the average BMR values in the table are higher for younger adults and lower for older groups. Strength training and staying active can help maintain muscle and improve your overall energy-burning capacity.

• Gender: On average, men tend to have more muscle and less body fat than women at the same weight and height, which leads to a higher metabolic rate.
• Body composition: Muscle tissue burns more calories at rest than fat. Two people with the same weight, height, and age can have very different BMR values if one has more muscle mass.

This is why the BMR calculator asks for gender and body stats—it helps provide a more personalized estimate of how much energy your body burns.

This online BMR calculator uses the Mifflin-St Jeor formula, which is considered a reliable and efficient method for estimating resting metabolic rate. However, it’s still an estimate, not a direct measurement. Real BMR can vary slightly depending on genetics, hormones, medications, exact body composition, and lifestyle. The tool is designed to give users a quick, automatic, and reasonably accurate starting point for planning calorie intake and fitness goals.

BMR isn’t completely fixed. While genetics set part of the baseline, you can improve your metabolism over time. The most effective strategies are:

• Building muscle with regular strength training
• Increasing daily activity (walking, standing, taking the stairs)
• Avoiding extreme diets that cause muscle loss

These changes help your body burn more energy at rest, which means a higher BMR and more flexibility in your calorie intake for long-term health-focused goals.

You should recalculate BMR whenever there’s a notable change in your stats or lifestyle, for example:

• Your weight changes by about 5–10%
• Your activity level shifts (e.g., you start or stop working out regularly)
• Your training style changes significantly (like adding heavy strength training)
• As you age, especially every few years