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Poland BMR calculator
Even lying still all day, your body burns energy to pump blood, breathe, keep warm and repair itself. That floor is your basal metabolic rate, and it is the single biggest part of how many calories you use in a day. Enter your sex, age, height and weight and the tool estimates your BMR two ways, by the modern Mifflin-St Jeor equation and by the older revised Harris-Benedict one, so you can see how close they land. It also shows the figure broken down per hour and the daily total for a person who barely moves. Knowing this number is the starting point for any plan to lose, hold or gain weight.
BMR is the energy your body burns at complete rest just to keep working. It is an estimate from height, weight, age and sex; real figures vary with muscle, genetics and health. To plan weight change, use the calorie calculator, which folds in your activity level.
How it works
- Choose your sex, since the equations use different constants for men and women.
- Enter your age in years, your height and your current weight.
- The Mifflin-St Jeor equation, the one dietitians most often use today, gives the headline figure.
- The revised Harris-Benedict equation is shown beside it as a cross-check; the two usually agree within a few percent.
- You also see the rate per hour and the daily need at a sedentary activity level, which is BMR multiplied by 1.2.
BMR (Mifflin-St Jeor) = 10 x kg + 6.25 x cm - 5 x age + s, where s is +5 for men and -161 for women
The Mifflin-St Jeor equation weights body weight most heavily, adds a smaller amount for height, and subtracts a little for each year of age, then applies a sex constant. The revised Harris-Benedict equation uses the same inputs with different coefficients. Both return calories per day at rest; an activity multiplier turns that into a full daily total.
- kg
- body weight in kilograms
- cm
- height in centimetres
- age
- age in completed years
- s
- sex constant: +5 for men, -161 for women
Activity multipliers applied to BMR
| Sedentary | BMR x 1.2 | desk job, little or no exercise |
| Lightly active | BMR x 1.375 | light exercise 1 to 3 days a week |
| Moderately active | BMR x 1.55 | moderate exercise 3 to 5 days |
| Very active | BMR x 1.725 | hard exercise 6 to 7 days |
Worked example
A 30-year-old man, 180 cm and 80 kg: Mifflin-St Jeor returns 1,780 kcal a day, while Harris-Benedict gives about 1,854, a gap of under 5 percent. That works out at roughly 74 kcal an hour at rest, and around 2,136 kcal a day once a sedentary lifestyle is folded in.
Key facts
- BMR usually accounts for 60 to 70 percent of the calories an average person burns in a day.
- Two people of the same weight can have different rates, because muscle burns more at rest than fat does.
- The figure is per day at total rest, so any movement at all pushes your real need above it.
- Mifflin-St Jeor and Harris-Benedict typically agree to within about 5 percent for a healthy adult.
Tips
- Use BMR as the floor, then apply an activity multiplier or the calorie calculator to get a daily target you can act on.
- Re-check the number after a noticeable change in weight, since it moves with your body mass.
- For weight loss, aim for a modest deficit below your full daily need rather than eating below BMR.
- Measure height and weight accurately; a 5 cm or 5 kg slip shifts the estimate by tens of calories.
Frequently asked questions
What is the difference between BMR and TDEE?+
BMR is what you burn at complete rest. Total daily energy expenditure, or TDEE, adds the calories spent on moving, digesting food and exercising. TDEE is always higher, and the calorie calculator works it out by applying an activity multiplier to your BMR.
Which equation should I trust?+
Mifflin-St Jeor, published in 1990, tends to be the more accurate for the general population and is the one most clinicians reach for. Harris-Benedict, revised in 1984, is shown here for comparison and reads slightly higher for many people.
Why does sex change the result?+
Men on average carry more muscle and less fat than women of the same height and weight, and muscle burns more energy at rest. The equations capture that with separate constants for each.
Does BMR fall as I age?+
Yes, gradually, mostly because muscle mass tends to decline with age. The equations subtract a few calories for each year, which is why an older person has a lower estimate than a younger one of the same build.
Can I raise my BMR?+
Building and keeping muscle is the most durable lever, since muscle is more metabolically active than fat. Crash dieting does the opposite and can lower it, as the body adapts to fewer calories.
Things to watch
- This is general guidance, not medical advice; a doctor or dietitian can tailor figures to your health.
- The equations are built for healthy adults and do not fit children, pregnancy or some medical conditions.
- Eating below your BMR for long stretches is not advisable without professional supervision.
Sources
- A new predictive equation for resting energy expenditure in healthy individuals (Mifflin et al., 1990) · American Journal of Clinical Nutrition
- The Harris Benedict equation reevaluated (Roza & Shizgal, 1984) · American Journal of Clinical Nutrition
Last updated: 2026
This is an estimate for general guidance, not financial, tax, legal or medical advice. Figures can change and individual circumstances vary. Always confirm with the official sources listed before making decisions.
Reviewed by Vikas Dulgunde.