Your BMR is the calorie number your body needs before you even get out of bed. Everything else, movement, exercise, digestion, gets added on top of it.
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BMR Calculator
Your Basal Metabolic Rate, the calories your body burns at complete rest, using the Mifflin-St Jeor equation.
Runs entirely in your browser. Nothing you enter is sent anywhere. Want your total daily calorie burn, not just resting? Try the Calorie Calculator, which adds your activity level on top of this number.
Why Mifflin-St Jeor, and what the second number is for
Mifflin-St Jeor (1990) is the equation the Academy of Nutrition and Dietetics currently recommends as the most accurate for estimating resting energy needs in most adults, and it's what this calculator uses as the headline number. The results table below also shows the older Harris-Benedict equation (revised 1984) for comparison, since it's still the number a lot of other calculators and older nutrition materials quote, it tends to run a little higher than Mifflin-St Jeor. Both are population-average estimates, not a measurement of your actual metabolism, which can only be measured directly with indirect calorimetry.
BMR calculator FAQ
What is BMR?
Basal Metabolic Rate: the calories your body burns just to stay alive at complete rest, breathing, circulating blood, maintaining body temperature, before you add any movement, exercise or digestion on top.
How is BMR different from TDEE?
BMR is your resting number alone. TDEE (Total Daily Energy Expenditure) multiplies BMR by an activity factor to estimate what you actually burn across a full day including exercise and general movement. Our Calorie Calculator adds that step and a goal-based target on top of this BMR figure.
Which formula is more accurate, Mifflin-St Jeor or Harris-Benedict?
Mifflin-St Jeor (1990) is the equation modern nutrition guidance recommends as more accurate for most adults today. Harris-Benedict, originally from 1919 and revised in 1984, tends to run a little higher and is shown here mainly because a lot of older tools and materials still quote it.
Can BMR be measured directly instead of estimated?
Yes, through indirect calorimetry, breathing into a device that measures oxygen consumption and carbon dioxide output at rest. It is the gold standard but requires clinical or lab equipment. Formula-based estimates like this one are a practical substitute for everyday use.
Is my data private?
Yes. Every calculation runs in your browser. Nothing you enter is sent to a server, logged, or stored.
Free BMR calculator by ANUPRESS
Why Mifflin-St Jeor over the older formula
Harris-Benedict dates back to 1919, revised once in 1984, and it’s still what a lot of calculators and diet books quote by default. Mifflin-St Jeor (1990) was validated against a larger, more contemporary population and is what the Academy of Nutrition and Dietetics currently recommends as the more accurate estimate for most adults, which is why it’s the headline number here rather than a legacy default nobody’s revisited.
BMR is a floor, not a target
Eating at or below your BMR for an extended period isn’t a shortcut, your body still needs energy for actual daily activity on top of resting functions, and chronically under-fueling even resting needs works against you rather than for you. BMR is useful as a baseline for the next calculation, working out your full daily energy needs, not as a number to eat down to.
From BMR to a real daily target
This number alone doesn’t tell you what to eat, it needs an activity multiplier and, usually, a goal on top. Our Calorie Calculator takes this exact BMR formula, adds your real activity level to get your full daily maintenance calories, then adjusts for weight loss, gain, or maintenance with a suggested macro split.