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BMR Calculator (Resting Metabolic Rate)

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A basal metabolic rate is what the body burns doing nothing at all: no walking, no digesting, no training. Enter an age, a weight, a height and the sex the equation needs, and this page estimates that resting figure with two published equations, prints both of them side by side, and leads with their average.

BMR Calculator - Danfio

https://danfio.com/tools/bmr-calculator/ - printed from this page

The equations were fitted on men and women separately, so they need one of the two.

Both equations subtract about 5 kcal for every year of age, so a decade older is roughly 50 kcal a day lower at rest.

The equations scale with body mass: each kilogram adds about 10 kcal to the Mifflin-St Jeor figure.

Height enters the equation at 6.25 kcal per centimeter, so it moves the estimate less than weight does.

Leave blank to name the files resting-rate.txt and .csv.

Results update as you type. Nothing leaves your device.

Resting rate, averaged from two published equations

1,439 kcal

The equations put your resting burn at about 1,439 kcal a day - roughly 60 kcal an hour - which is what a day costs before movement, food or training. It is a resting figure, not a ration and not a target: the page that turns it into a day is the Calorie Calculator.

Mifflin-St Jeor
1,414 kcal
Harris-Benedict (revised)
1,464 kcal
Average used here
1,439 kcal
Per hour at rest
60 kcal
Gap between the equations
50 kcal 3.5% of the average

Each equation on its own

EquationResting ratePer hourDifference from the average
Mifflin-St Jeor (1990)1,414 kcal58.9 kcal−24.9 kcal
Harris-Benedict (revised 1984)1,464 kcal61 kcal+24.9 kcal
Average of the two1,439 kcal60 kcal0 kcal

Both equations were fitted on their own populations and disagree by a few percent here; Harris-Benedict is the older one and tends to run higher. Printing them side by side, each with its distance from the average, is the honest way to show how much precision a resting-rate estimate has - the gap between them is the error bar.

What moves the resting rate, five units at a time

ChangeResting rateDifference from your rate
+5 kg1,487 kcal+48.1 kcal
−5 kg1,391 kcal−48.1 kcal
+5 years1,416 kcal−23.3 kcal
−5 years1,462 kcal+23.3 kcal
+5 cm1,462 kcal+23.4 kcal
−5 cm1,416 kcal−23.4 kcal

One input at a time, everything else held still, so the table says which of the three your number is most sensitive to - not what would happen to you. A real body is not a set of independent dials: losing weight changes the resting rate itself.

BMR and resting metabolic rate (RMR) are two names for a measurement taken under different conditions: BMR under strict laboratory conditions, after an overnight fast and a night of sleep; RMR under looser ones, which usually reads a few percent higher. The equations here predict a figure of the RMR kind, and "BMR" is the name the search uses for it - one number either way: what the body burns doing nothing.
A resting rate is not a ration. It excludes movement, the energy spent digesting food and every kind of training, which is why it is always lower than what a whole day costs. Turning it into a day means choosing a level of movement and accepting a much wider error bar, and that calculation belongs to the Calorie Calculator rather than here.

What this estimate is, and is not

  • A resting rate is an estimate from a population equation, not a measurement of you. For an individual it is usually within about 10% and sometimes worse: body composition, hormones, sleep and medication all move the real figure, and none of them is in the equation.
  • Two respected equations, a few percent apart. The page prints both and uses their average rather than promoting one of them to the truth.
  • This is arithmetic, not medical advice, and it is not appropriate for pregnancy, recovery from an eating disorder, a metabolic or kidney condition, or anybody taking medication that affects weight. Those need a clinician rather than a calculator.

It also prints what the average comes to in an hour, moves each of the three inputs by five units so you can see which one your own number is most sensitive to, and spells out the difference between BMR and RMR. What it does not do is turn the number into a daily target: that is the calorie calculator, and this page names it instead of quietly answering its question too.

About this bmr calculator

A BMR calculator answers a narrower question than a calorie calculator, and this page is built around that boundary. What it computes is the resting figure: the energy a body spends on its own maintenance, before movement, digestion or training. What it refuses to compute is a daily target, a deficit, a rate of change or a macronutrient split, because those are different calculations with different inputs and a much wider error bar - and the site already has a calorie calculator for all of them.

The page prints both published equations, each with its own hourly figure and its distance from the average it leads with, and explains that BMR is a laboratory measurement while the equations predict the looser resting metabolic rate. It also moves each input by five units so a visitor can see which one their own number depends on most: weight, in both equations, by roughly twice the effect of age or height.

Where it should not be used: this is arithmetic about a population. It is not appropriate for pregnancy, recovery from an eating disorder, a metabolic or kidney condition, or anybody taking medication that affects weight - those need a clinician rather than a calculator. A resting rate is also not a level to eat down to: eating below what a body needs for its own maintenance is a decision for a dietitian, not a form. Not a medical device and not a diagnosis; talk to a clinician.

How this bmr calculator works

The two equations behind the number

Mifflin-St Jeor (1990) multiplies weight by 10, height in centimeters by 6.25 and age by 5, then adds 5 for men and subtracts 161 for women. Harris-Benedict was published earlier and revised in 1984 with its own coefficients, and it usually lands a little higher than Mifflin-St Jeor.

Both equations were fitted on their own populations, and they disagree by a few percent on any given body. This page prints both, each with its distance from the average, because that gap is the honest measure of how much precision a resting-rate estimate actually has. A page that printed one number would look more precise without being more accurate.

BMR and RMR are two names for a measurement

Basal metabolic rate is measured under strict conditions: after an overnight fast, after a night of sleep, lying still in a thermoneutral room. Resting metabolic rate is measured under looser ones, so it usually reads a few percent higher. In practice the two names are used interchangeably, and the equations above predict a figure of the RMR kind.

The page uses BMR because that is the name people search for, and states which measurement the number is closest to, rather than letting a name imply a laboratory grade of certainty.

What a day costs on top of rest

A resting rate is not a ration. Digesting food costs energy, and so does every step, every shift at work and every training session; added together they are usually larger than the resting figure itself. Turning rest into a whole day means estimating movement, which is self-reported, varies day to day and carries a much wider error bar than the equations do.

That calculation belongs to the calorie calculator, which is why this page stops at rest and links across rather than growing a target of its own.

Which input moves the number most

At the default body on this page - a 35-year-old woman at 70 kg and 168 cm - five kilograms of weight moves the average by about 48 kcal, while five years of age or five centimeters of height move it by roughly 23 kcal each. Weight carries the largest coefficient in both equations, so the weight box is the one that decides the answer.

The table moves one input at a time with everything else held still, which is what makes it readable - and also what makes it a sensitivity test rather than a forecast. A real body is not a set of independent dials: losing weight changes the resting rate itself.

Worked examples

Each example below was run through the calculator on this page when the site was built, so the numbers match what you see when you enter the same inputs.

A 35-year-old woman at 70 kg and 168 cm

Sex used by the equation: Female · Age: 35 years · Weight: 70 kg · Height: 168 cm · Download file name: —

Resting rate, averaged from two published equations

1,439 kcal

The equations put your resting burn at about 1,439 kcal a day - roughly 60 kcal an hour - which is what a day costs before movement, food or training. It is a resting figure, not a ration and not a target: the page that turns it into a day is the Calorie Calculator.

Mifflin-St Jeor: 1,414 kcal · Harris-Benedict (revised): 1,464 kcal · Average used here: 1,439 kcal · Per hour at rest: 60 kcal

The two equations read 1,414 and 1,464 kcal, the average is 1,439 kcal, and that is about 60 kcal an hour. Both equations sit beside the average so the spread between them stays visible.

The same body ten years later

Sex used by the equation: Female · Age: 45 years · Weight: 70 kg · Height: 168 cm · Download file name: —

Resting rate, averaged from two published equations

1,392 kcal

The equations put your resting burn at about 1,392 kcal a day - roughly 58 kcal an hour - which is what a day costs before movement, food or training. It is a resting figure, not a ration and not a target: the page that turns it into a day is the Calorie Calculator.

Mifflin-St Jeor: 1,364 kcal · Harris-Benedict (revised): 1,420 kcal · Average used here: 1,392 kcal · Per hour at rest: 58 kcal

Ten extra years take the average to about 1,392 kcal: both equations subtract for age, about 4.7 kcal a year between them, because lean mass tends to fall. It is an average effect, not a rule about one person.

A man of the same height and weight

Sex used by the equation: Male · Age: 35 years · Weight: 70 kg · Height: 168 cm · Download file name: —

Resting rate, averaged from two published equations

1,607 kcal

The equations put your resting burn at about 1,607 kcal a day - roughly 67 kcal an hour - which is what a day costs before movement, food or training. It is a resting figure, not a ration and not a target: the page that turns it into a day is the Calorie Calculator.

Mifflin-St Jeor: 1,580 kcal · Harris-Benedict (revised): 1,634 kcal · Average used here: 1,607 kcal · Per hour at rest: 67 kcal

The male coefficients put the average near 1,607 kcal, roughly 168 kcal above the female figure for the same body. Both equations fit men and women separately, which is why the page asks for one of the two rather than leaving it out.

A smaller body at 55 kg

Sex used by the equation: Female · Age: 35 years · Weight: 55 kg · Height: 168 cm · Download file name: —

Resting rate, averaged from two published equations

1,295 kcal

The equations put your resting burn at about 1,295 kcal a day - roughly 53.9 kcal an hour - which is what a day costs before movement, food or training. It is a resting figure, not a ration and not a target: the page that turns it into a day is the Calorie Calculator.

Mifflin-St Jeor: 1,264 kcal · Harris-Benedict (revised): 1,325 kcal · Average used here: 1,295 kcal · Per hour at rest: 53.9 kcal

Fifteen kilograms lighter comes to about 1,295 kcal, some 144 kcal below the 70 kg figure - weight carries the largest coefficient in both equations, so it moves the answer more than age or height do.

Frequently asked questions

What is the difference between BMR and RMR?

They name the same kind of measurement taken under different conditions. BMR is measured in a laboratory after an overnight fast and a night of sleep; RMR is measured under looser resting conditions and usually comes out a few percent higher. The equations on this page predict a figure of the RMR kind, and BMR is the name most people search for.

Why does this page show two equations instead of one?

Because two respected equations estimate the same thing and disagree by a few percent on the same body - Mifflin-St Jeor tends to sit lower and Harris-Benedict higher. Printing both, each with its distance from the average, is a more honest picture of the precision available than one number presented on its own.

Is my BMR the number of calories I should eat?

No. A resting rate excludes movement, the energy spent digesting food and training, so it is always lower than what a whole day costs - and it is a measurement of what a body burns, not a target to eat down to. The daily question belongs to the calorie calculator, which adds a movement estimate and states how wide its own error bar is.

How accurate is a BMR calculator?

For an individual, usually within about 10% and sometimes worse. The equations predict a population average for a height, weight, age and sex, and real people vary around that average for reasons the equation cannot see: body composition, hormones, sleep and medication. The gap between the two equations on this page is the visible part of that uncertainty.

Why does the estimate fall as I get older?

Both equations subtract a fixed amount per year of age, about 5 kcal a year in Mifflin-St Jeor and 4.3 in the revised Harris-Benedict, because lean mass - the metabolically active tissue - tends to fall with age across a population. It is an average effect: the equations do not know how much muscle any one person has kept.

Can I raise my resting rate?

Muscle tissue burns more at rest than fat tissue does, so training that adds and keeps lean mass raises the resting figure somewhat, and the effect is smaller and slower than most marketing suggests. The equations cannot tell whether you train, so they keep predicting the same number for the same height, weight and age.

Assumptions and sources

  • Mifflin MD et al., A new predictive equation for resting energy expenditure in healthy individuals, American Journal of Clinical Nutrition 51 (1990).
  • Roza AM and Shizgal HM, The Harris Benedict equation reevaluated, American Journal of Clinical Nutrition 40 (1984): the revised coefficients used here.
  • The BMR and RMR distinction, and the conditions each measurement is taken under, are described in the standard resting-indirect-calorimetry protocol used across the clinical nutrition literature.
  • The two equations, their average and the hourly figure are printed side by side; neither equation is a measurement of your own body.

Last reviewed 2026-10-08. Not a medical device and not a diagnosis; talk to a clinician. Read the full disclaimer.

Where a figure on this page comes from an official agency — HUD, IRS, FICO or a state body — the site keeps a dated snapshot of the source page in its sources library, and a scheduled job re-checks that snapshot, so the number can be traced back to the document it came from.

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