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Basal Metabolic Rate (BMR) is the number of calories your body requires to sustain basic life functions at complete rest — including breathing, circulation, and cell production. The Mifflin-St Jeor formula (1990) is generally considered more accurate for modern populations, while the Harris-Benedict formula (1919, revised 1984) is historically significant. Multiply your BMR by an activity factor to get your Total Daily Energy Expenditure (TDEE).
Review the inputs carefully and treat the output as an estimate. For decisions involving money, taxes, health, law, or security, compare the result with trusted professional guidance when needed.
Which formula is more accurate?
Studies suggest the Mifflin-St Jeor formula is more accurate for most adults. The Harris-Benedict formula tends to overestimate BMR slightly.
Does BMR change over time?
Yes. BMR decreases with age and tends to be influenced by muscle mass. Building muscle can help maintain a higher BMR.
Can I use BMR directly for meal planning?
BMR is the minimum calorie floor. For meal planning, multiply by your activity factor to get TDEE, then adjust for your goals.
Calorie Calculator
Calculate your daily calorie needs using the Mifflin-St Jeor formula based on age, gender, height, weight, and activity.
Open toolTDEE Calculator
Calculate your Total Daily Energy Expenditure — the calories you burn each day including all activity.
Open toolMacro Calculator
Calculate your daily macronutrient targets — protein, carbohydrates, and fat — based on your calorie goal and fitness objectives.
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