BMR Calculator
Calculate your Basal Metabolic Rate and estimate how many calories your body needs at rest each day.
Calculate Your BMR
Your Estimated BMR
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Estimated calories your body uses each day at complete rest.
Mifflin–St Jeor Formula
Quick Examples
70 kg · 175 cm Calculate →
60 kg · 165 cm Calculate →
85 kg · 180 cm Calculate →
75 kg · 170 cm Calculate →
What is the BMR Calculator used for?
A BMR Calculator estimates the number of calories your body may need to support basic functions while at complete rest. It can give you a starting point for understanding your resting calorie needs before considering exercise and other daily activities. The result is often used alongside information about activity level when estimating overall daily energy requirements.
What does BMR mean?
BMR stands for Basal Metabolic Rate. It refers to the amount of energy your body needs to carry out essential functions at rest, such as breathing, circulation, and maintaining normal body processes. A BMR estimate does not represent all the calories you use during a normal day because walking, working, exercising, and other activities require additional energy.
What information is needed to calculate BMR?
Most BMR calculations require your age, sex, height, and weight. Height and weight should be entered using the units requested by the calculation method. These details are used to estimate your resting metabolic rate. Unlike a daily calorie calculation, BMR focuses specifically on the energy required for basic bodily functions at rest rather than adding calories used through normal physical activity.
How do age, height, weight, and sex affect BMR?
Each of these factors can influence an estimated metabolic rate. In general, body weight and height affect the amount of energy needed to support the body, while age is included because estimated energy requirements tend to change over a lifetime. Sex is also included in commonly used BMR equations because the formulas use different constants. These factors work together rather than determining BMR separately.
Can BMR change when body weight changes?
Yes. A change in body weight can change an estimated BMR because weight is one of the variables used in common BMR equations. For example, entering a lower body weight may produce a lower BMR estimate, while entering a higher weight may produce a higher estimate, all else being equal. Changes in body composition and other factors can also affect actual energy expenditure.
What factors can affect an estimated BMR?
The estimate can differ from actual resting energy use because standard equations cannot capture every individual difference. Body composition, genetics, hormonal conditions, temperature, illness, medications, and changes in physiological state can influence energy expenditure. The information entered also matters; an incorrect age, height, or weight can change the calculation. For this reason, a calculated BMR should be viewed as an estimate rather than a direct measurement.