BMR Calculator
Enter your age, sex, height and weight to estimate your basal metabolic rate (BMR), the calories your body uses at rest in a day, and see what that becomes at each activity level.
Last updated November 4, 2026
Used only by the formula
Result
Your BMR is about 1,433 kcal a day
| Result | Value |
|---|---|
| BMR (Mifflin-St Jeor) | 1,433 kcal per day |
| Same in kilojoules | 5,996 kJ per day |
| Per hour | 59.7 kcal |
| Activity level | Factor | Calories per day |
|---|---|---|
| Sedentary (little or no exercise) | × 1.2 | 1,720 kcal |
| Light (exercise 1-3 days a week) | × 1.375 | 1,970 kcal |
| Moderate (exercise 3-5 days a week) | × 1.55 | 2,221 kcal |
| Active (hard exercise 6-7 days a week) | × 1.725 | 2,472 kcal |
| Very active (physical job or twice-daily training) | × 1.9 | 2,723 kcal |
General estimate only, not medical advice. Talk to a qualified health professional about your own situation. BMR is the energy your body uses at complete rest; it does not include movement or exercise. The activity factors are common rules of thumb.
Show the work
Formula: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 (men) or − 161 (women). Daily calories = BMR × activity factor.
- Convert to metric: weight 150 lb × 0.45359237 = 68.039 kg; height 67 in × 2.54 = 170.18 cm.
- BMR = 10 × 68.039 + 6.25 × 170.18 − 5 × 30 − 161 = 1,433.01 kcal per day (inputs shown rounded to 3 decimals).
- sedentary: 1,433.01 × 1.2 = 1,720 kcal.
- light: 1,433.01 × 1.375 = 1,970 kcal.
- moderate: 1,433.01 × 1.55 = 2,221 kcal.
- active: 1,433.01 × 1.725 = 2,472 kcal.
- very-active: 1,433.01 × 1.9 = 2,723 kcal.
Result: Your BMR is about 1,433 kcal a day
How BMR is calculated
BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 (men) or − 161 (women)
Basal metabolic rate is the energy your body needs to keep working while you lie still: breathing, circulation, temperature control and cell repair. It excludes digesting food, walking around and exercise. For most people it is the largest part of daily energy use.
This calculator uses the Mifflin-St Jeor equation, published in 1990 from measurements of healthy adults. Weight goes in kilograms and height in centimeters, so if you choose pounds, feet and inches they are converted first (1 lb = 0.45359237 kg, 1 in = 2.54 cm). The result is in kilocalories per day; multiply by 4.184 for kilojoules.
The table under your result scales BMR by five activity factors (1.2 to 1.9) as a quick look at what resting energy becomes in daily life. These factors are conventional rules of thumb, not measured constants. This page is about the resting rate itself: for one activity-adjusted figure with calorie targets to lose or gain weight, use the TDEE calculator, and for a range and a choice of equations, use the maintenance calorie calculator.
See how we calculate for the formulas, sources and review schedule behind every calculator.
Also useful alongside this calculator: TDEE Calculator, Protein Calculator and BMI Calculator.
This is an estimate, not medical advice
This calculator gives a general estimate from the published methods listed under Sources. It does not diagnose anything or replace advice from a doctor, dietitian or other qualified health professional, and individual needs differ. This page has not been reviewed by a medical professional.
BMR, resting metabolic rate and total daily energy
Strictly, BMR is measured after a night of fasting and rest in a controlled room, while resting metabolic rate (RMR) is measured under looser conditions and usually comes out slightly higher. Prediction equations such as Mifflin-St Jeor were fitted to resting measurements, so the number here is best read as your resting rate.
Total daily energy expenditure adds movement, exercise and the energy used to digest food on top of that resting rate. The activity table under your result shows that step in outline. The TDEE calculator builds on it with deficit and surplus targets, and the maintenance calorie calculator adds a range and alternative equations.
How accurate is a BMR estimate?
An equation uses only four inputs, so it cannot see muscle mass, genetics, hormones, medication or illness. Two people with the same numbers can differ by a couple of hundred calories a day. Treat the result as a reasonable average, not a measurement.
The equation was fitted to adults, and this page accepts ages 18 to 100. It is not designed for children, pregnancy or breastfeeding, or for people with medical conditions that change metabolism. If your weight changes over weeks in a way the estimate does not predict, trust the scale over the formula and adjust.
Sources
Official and primary sources for the statements on this page. Their authors have not reviewed or endorsed this page.
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51(2):241-247. Source of the Mifflin-St Jeor equation used here: 10 × weight (kg) + 6.25 × height (cm) − 5 × age, plus 5 for men or minus 161 for women
We could not verify a primary source for the activity factors (1.2 to 1.9); they are common rules of thumb.
The kilojoule conversion uses the thermochemical calorie, 1 kcal = 4.184 kJ.
How to use the BMR Calculator
- Choose US or metric units, then your sex and age in whole years.
- Enter your height and your current weight.
- Read your BMR in calories per day, and in kilojoules and per hour.
- Compare the activity table to find the row that matches a typical week, then use Copy, Print or Share.
Worked example
A 30-year-old man, 180 cm and 80 kg. BMR = 10 × 80 + 6.25 × 180 − 5 × 30 + 5 = 800 + 1,125 − 150 + 5 = 1,780 kcal per day, or about 7,448 kJ. Multiplying by each factor gives the daily totals below (halves round up).
| Result | Calories per day |
|---|---|
| BMR (resting) | 1,780 |
| Sedentary (× 1.2) | 2,136 |
| Light (× 1.375) | 2,448 |
| Moderate (× 1.55) | 2,759 |
| Active (× 1.725) | 3,071 |
| Very active (× 1.9) | 3,382 |
Frequently asked questions
What is a good BMR?
There is no good or bad figure. BMR rises with body size and is usually lower for women, older adults and people with less muscle, so compare it only with your own estimate over time.
Is BMR the same as the calories I should eat?
No. BMR covers resting needs only. Your daily total is higher once activity is included, and the right intake for weight loss or gain also depends on your health and goals.
Why does my BMR change when I lose weight?
The equation uses body weight, so a lower weight gives a lower estimate. Age in years also matters, with each extra year subtracting 5 calories a day.
Can I raise my BMR?
Having more lean mass tends to raise resting energy use, but the effect is modest and this calculator cannot measure it, so it only reacts to weight, height, age and sex.
Are my numbers stored or sent anywhere?
No. The calculation runs in your browser and nothing you enter is saved or uploaded.