How the BMR calculator works
Enter your sex, age, height, and weight, and the tool estimates your basal metabolic rate, the energy your body uses at complete rest to keep basic functions running. It uses the Mifflin-St Jeor equation, one of the most accurate widely used formulas, and then shows rough daily maintenance estimates at several activity levels.
What BMR means
Your BMR is the calories you would burn in a day doing nothing but resting. It is the largest part of most people total energy use. Multiplying BMR by an activity factor gives a rough estimate of the calories needed to maintain your current weight given how active you are, from sedentary to very active.
Activity multipliers
The maintenance figures use common multipliers: about 1.2 for sedentary, 1.375 for light activity, 1.55 for moderate, and 1.725 for very active. These are population averages and individuals vary widely based on muscle mass, genetics, job, and daily movement, so treat them as starting estimates rather than precise numbers.
Using the estimate responsibly
These numbers describe roughly what it takes to maintain weight, not a prescription to eat more or less. Energy needs are personal and change over time, and healthy nutrition is about much more than a calorie count. For goals around weight, performance, or health conditions, work with a doctor or registered dietitian. This tool is general information, not medical advice.
Frequently asked questions
What is BMR? The calories your body uses at complete rest for basic functions like breathing and circulation.
Which formula does this use? The Mifflin-St Jeor equation, a widely used and reasonably accurate estimate.
Is the maintenance number a calorie target? No, it is a rough estimate; for personalized targets see a professional.
Related calculators: BMI, Body Fat, Heart Rate Zones.