BMI Calculator
Use this free BMI calculator to find your body mass index in metric or imperial units. Whether you need a BMI calculator for women, for men, or just a quick health check, you will see your BMI category, your position on the WHO BMI chart, and the healthy weight range for your height. The result updates instantly as you type.
What this means: Maintain your current weight. BMI is a screening tool, not a diagnosis. Muscle mass, age, and body composition affect the meaning of your number. Talk to a doctor for a complete health picture.
BMI categories explained
WHO classification with health risk indication for each range.
| BMI range | Category | Health risk |
|---|---|---|
| Below 16.0 | Severely underweight | High (nutritional deficiency) |
| 16.0 to 18.4 | Underweight | Moderate |
| 18.5 to 24.9 | Normal weight | Lowest |
| 25.0 to 29.9 | Overweight | Increased |
| 30.0 to 34.9 | Obesity Class I | Moderate |
| 35.0 to 39.9 | Obesity Class II | Severe |
| 40.0 and above | Obesity Class III | Very severe |
Healthy weight range by height
Weight range corresponding to BMI 18.5 to 24.9 for common heights.
| Height | Healthy weight (kg) | Healthy weight (lbs) |
|---|---|---|
| 150 cm (4 ft 11 in) | 41.6 - 56.0 kg | 92 - 124 lbs |
| 155 cm (5 ft 1 in) | 44.4 - 59.8 kg | 98 - 132 lbs |
| 160 cm (5 ft 3 in) | 47.4 - 63.7 kg | 104 - 141 lbs |
| 165 cm (5 ft 5 in) | 50.4 - 67.8 kg | 111 - 149 lbs |
| 170 cm (5 ft 7 in) | 53.5 - 71.9 kg | 118 - 159 lbs |
| 175 cm (5 ft 9 in) | 56.7 - 76.3 kg | 125 - 168 lbs |
| 180 cm (5 ft 11 in) | 59.9 - 80.7 kg | 132 - 178 lbs |
| 185 cm (6 ft 1 in) | 63.3 - 85.2 kg | 139 - 188 lbs |
| 190 cm (6 ft 3 in) | 66.8 - 89.9 kg | 147 - 198 lbs |
What this calculator shows you
Metric and imperial
Switch between kg/cm and lbs/ft+inches with one click.
Visual BMI scale
A colored bar shows where you sit on the underweight to obese spectrum.
Healthy weight range
The tool shows the weight range that corresponds to a healthy BMI for your height.
WHO standard categories
Underweight, normal, overweight, and obesity classes I, II, III as defined by the World Health Organization.
No data stored
Everything runs in your browser. Your weight and height never leave this page.
Mobile friendly
Big number inputs and a clear result panel on any screen size.
When to check your BMI
Health screening
Get a quick check on whether your weight is in the healthy range for your height before a doctor visit.
Weight loss tracking
Monitor your BMI over weeks to see if your weight management plan is moving you toward a healthier range.
Insurance applications
Some health insurance forms ask for current BMI. Calculate it accurately here in a few seconds.
Fitness goal setting
See what target weight would put you in the normal BMI range and use that as a long-term goal.
Annual physicals
Your BMI is part of every routine checkup. Know your number before walking into the doctor's office.
School and military fitness
Some programs and entry requirements include BMI cutoffs. Check yours against the published thresholds.
About Body Mass Index
What is BMI?
Body Mass Index (BMI) is a number calculated from your weight and height that provides a rough indicator of whether you are at a healthy weight. It was developed in the 1830s by Belgian mathematician Adolphe Quetelet and was originally called the Quetelet Index. The World Health Organization adopted body mass index as a population-level health metric in the 1990s, and it is now the most widely used screening figure in clinics, gyms, and insurance forms around the world. A BMI calculator simply automates the math so you can read your result in seconds.
How BMI is calculated
The formula is straightforward: weight in kilograms divided by height in meters squared. So a 70 kg person who is 1.75 m tall has a BMI of 70 / (1.75 x 1.75) = 22.86. That falls in the normal range. For imperial units, the formula becomes (weight in pounds / height in inches squared) multiplied by 703. Our body mass index calculator runs both versions for you, so you can enter kg and cm or lbs and feet without converting anything yourself.
BMI calculator for women
Many people search specifically for a BMI calculator for women or a BMI calculator female because they want to know whether the standard ranges apply to them. The math is identical: a womens BMI calculator uses the same weight and height formula as one for men. The healthy band of 18.5 to 24.9 is not adjusted by sex in the official WHO system. What does differ is body composition. At the same body mass index, women naturally carry more essential body fat than men, partly for reproductive health. A BMI calculator for ladies therefore gives a reliable screening number, but a healthy-looking BMI in a woman can still correspond to a different body fat percentage than the same number in a man.
BMI calculator female ranges and what is healthy
For a body mass index calculator female result, a value between 18.5 and 24.9 is considered a healthy weight, the same as the general adult range. A BMI under 18.5 may suggest underweight, which can affect bone density, hormones, and menstrual regularity. A BMI of 25 and above is classified as overweight, and 30 and above as obese. These thresholds give a useful starting point, but a doctor will also consider age, muscle mass, waist size, and overall health before drawing any conclusion.
How to read a BMI chart
A BMI chart, sometimes called a BMI index chart, lets you find your category without doing any arithmetic. Height runs along one axis and weight along the other, and the cell where your row and column meet is shaded by category: underweight, normal, overweight, or obese. To read a BMI chart for women or men, locate your height, move across to your weight, and note the color band. The BMI categories table and the healthy-weight-by-height table higher up this page work the same way. A BMI table for women is identical to one for men because, again, the formula does not change by sex.
BMI categories explained
The WHO BMI categories are: underweight below 18.5, normal weight from 18.5 to 24.9, overweight from 25.0 to 29.9, and obesity at 30.0 and above. Obesity is further split into Class I (30.0 to 34.9), Class II (35.0 to 39.9), and Class III (40.0 and above). Each step up the BMI chart is associated with a higher statistical risk of conditions such as type 2 diabetes, high blood pressure, and heart disease, while being underweight carries its own risks including weakened immunity and nutrient deficiency. The category is a flag for a conversation with a clinician, not a diagnosis on its own.
BMI for men vs women
Because BMI uses only height and weight, the number itself is calculated the same way for everyone. The practical difference between men and women is in interpretation. Men tend to carry more lean muscle and store fat around the abdomen, while women tend to store more fat around the hips and thighs and have a higher baseline body fat percentage. This means two people, one man and one woman, can share an identical BMI yet have meaningfully different body composition and health risk. That is why a BMI chart female reader and a male reader should both treat the result as a screening figure and pair it with measurements like waist circumference.
What BMI does not tell you
BMI does not measure body fat directly. It cannot distinguish between muscle and fat, between fat in your belly versus fat under your skin, or between healthy weight at different ages. A 25-year-old bodybuilder with a BMI of 28 likely has very low body fat. A 70-year-old with the same BMI may have lost muscle and gained fat. Both have the same BMI but very different health profiles.
Better measures of health
Waist circumference is a better predictor of metabolic disease risk than BMI alone. For men, a waist over 102 cm (40 inches) and for women over 88 cm (35 inches) signals increased risk. Body fat percentage, blood pressure, fasting glucose, and cholesterol provide a fuller picture of cardiovascular and metabolic health than weight alone. Using your BMI alongside these markers gives you a far more honest view of your health than any single number can.
Limitations of BMI
BMI is a population-level tool, which means it works well for describing groups but less well for any one individual. It does not account for muscle mass, bone density, age, ethnicity, or fat distribution. Highly muscular people often score in the overweight or obese range despite being very healthy, because the body mass index cannot tell that the extra weight comes from muscle. Older adults sometimes carry hidden fat without obvious overweight on the scale. Some research also suggests that health risk begins at a lower BMI for people of South Asian descent and a slightly higher one for some other groups. Treat your BMI as a useful starting point, not a final verdict.
BMI for athletes and special populations
Pregnant women, growing children, and elite athletes should not rely on BMI as a primary health indicator. During pregnancy, weight gain is expected and healthy, so a pre-pregnancy BMI is the more meaningful figure to track with a midwife or doctor. Children and teenagers use BMI-for-age percentile charts rather than the adult categories, because their bodies are still growing. Athletes are better served by body fat testing and performance metrics. For everyone else, a BMI calculator is a fast, free, and reasonable first check, and a good prompt to ask a professional for a fuller assessment if your number sits outside the normal range.
BMI equals your weight in kilograms divided by the square of your height in meters. The formula: BMI = kg / (m x m). For imperial units: BMI = (lbs / (in x in)) x 703. Our calculator handles both unit systems automatically.
For adults, a BMI between 18.5 and 24.9 is classified as normal weight. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or higher is obese. These categories are defined by the World Health Organization.
BMI is a useful screening tool for the general adult population but has limitations. Muscular people can have a high BMI despite low body fat. Older adults may carry healthy weight at lower BMI ranges. BMI does not account for muscle mass, bone density, or fat distribution.
5 feet 10 inches is 70 inches (177.8 cm). 170 lbs is 77.1 kg. BMI = 77.1 / (1.778 x 1.778) = 24.4. This is at the top of the normal weight range (18.5 to 24.9).
The calculator shows your healthy weight range based on a BMI of 18.5 to 24.9. For someone 170 cm tall, the healthy range is about 53.5 to 71.9 kg (118 to 158 lbs). For 180 cm, the range is 59.9 to 80.7 kg (132 to 178 lbs).
The standard BMI calculation does not differentiate by sex. However, women naturally carry more body fat than men at the same BMI. Some health organizations recommend slightly different interpretation ranges for men versus women, especially regarding body fat distribution.
A BMI of 30 or higher is classified as obese. Within obesity, there are three classes: Class I (30 to 34.9), Class II (35 to 39.9), and Class III (40 and above, also called severe or morbid obesity). Higher classes carry greater health risks.
No. Children and teens (ages 2 to 19) use a different system called BMI-for-age percentiles, which accounts for growth and developmental changes. Our calculator is designed for adults aged 20 and over.
Not always. Muscular athletes often have BMI values in the overweight or obese range despite very low body fat. For athletes, body fat percentage and waist-to-hip ratio are more accurate health indicators than BMI alone.
Lowering BMI requires losing weight, which means consuming fewer calories than you burn. Aim for a deficit of 500 to 750 calories per day for sustainable loss of 0.5 to 0.75 kg (1 to 1.5 lbs) per week. Combine reduced intake with regular exercise. Consult a doctor for personalized guidance.
A BMI calculator for women uses exactly the same formula as one for men: weight divided by height squared. The healthy range of 18.5 to 24.9 is not adjusted by sex in the official WHO system. The main difference is interpretation, since women naturally carry more body fat than men at the same BMI.
For most adult women, a healthy BMI falls between 18.5 and 24.9, the same range used for men. A value below 18.5 may indicate underweight, which can affect bone density and menstrual health, while 25 and above is classed as overweight. Age, muscle mass, and waist size should also be considered.
A BMI chart, or BMI index chart, has height on one axis and weight on the other. Find your height, move across to your weight, and read the shaded category where they meet. A BMI table for women is identical to one for men, because the calculation does not change by sex.
No. A BMI chart female reader sees the same numbers as a male reader, because body mass index is calculated only from height and weight. The category bands of underweight, normal, overweight, and obese are the same for both. Only the interpretation around body composition differs.
This body mass index calculator accepts both metric and imperial units. You can enter your weight in kilograms with height in centimeters, or weight in pounds with height in feet and inches. The tool converts automatically and shows your BMI, category, and healthy weight range.