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BMI Calculator

Find your body mass index, see your weight category, and check the healthy weight range for your height.

  • Free to use
  • No sign-up
  • Numbers stay in your browser

Last updated:

Your measurements

years

This calculator is for adults aged 20 and over.

Height
ft
in
lb

Your weight in pounds.

The boxes start with example numbers. Change them to your own, then press Calculate.

Your BMI result

Your BMI
23.4
kg/m² · Healthy weight

Your BMI of 23.4 is in the healthy weight range (18.5 to 24.9). BMI is a screening measure, not a diagnosis.

  • Healthy BMI range18.5 – 24.9kg/m² for adults
  • Healthy weight for your height129 – 174 lb58 – 79 kg at 5 ft 10 in
  • BMI Prime0.94your BMI ÷ 25

BMI categories for adults

CategoryBMI (kg/m²)
Severe thinnessBelow 16
Moderate thinness16 – 16.9
Mild thinness17 – 18.4
Healthy weight (normal)18.5 – 24.9
Overweight25 – 29.9
Obese class I30 – 34.9
Obese class II35 – 39.9
Obese class III40 or more

World Health Organization classification for adults aged 20 and over. Your row is highlighted.

How to calculate BMI

BMI is your weight in kilograms divided by your height in meters, squared.

BMI = weight (kg) ÷ height (m)²
BMI = 703 × weight (lb) ÷ height (in)²

In this example: 703 × 163 lb ÷ 70 in² = 114,589 ÷ 4,900 = 23.4.

BMI chart by height

HeightHealthy weight (lb)Healthy weight (kg)
4 ft 10 in89 – 119 lb40 – 54 kg
5 ft 0 in95 – 127 lb43 – 58 kg
5 ft 2 in101 – 136 lb46 – 62 kg
5 ft 4 in108 – 145 lb49 – 66 kg
5 ft 6 in115 – 154 lb52 – 70 kg
5 ft 8 in122 – 164 lb55 – 74 kg
5 ft 10 in129 – 174 lb58 – 79 kg
6 ft 0 in136 – 184 lb62 – 83 kg
6 ft 2 in144 – 194 lb65 – 88 kg
6 ft 4 in152 – 205 lb69 – 93 kg

Weights that give a BMI from 18.5 to 24.9, rounded to the nearest pound or kilogram. The same chart applies to women and men.

BMI calculator for women and men

The adult BMI formula and the categories are the same for women and men. On average, women carry more body fat than men at the same BMI, so BMI is best used with other measures.

Same BMI range for both

What your BMI number means

BMI 17
Mild thinness
BMI 18
Mild thinness
BMI 20
Healthy weight
BMI 22
Healthy weight
BMI 24
Healthy weight
BMI 25
Overweight
BMI 26
Overweight
BMI 27
Overweight
BMI 30
Obese class I
BMI 31
Obese class I
BMI 35
Obese class II
BMI 40
Obese class III

What does BMI stand for?

BMI stands for Body Mass Index. It is a quick way to compare your weight with your height. It is a screening tool: it does not measure body fat, so it cannot say how healthy you are on its own.

To look at body fat, try the Body Fat Calculator.

What is included

  • Your BMI and your weight category
  • A scale showing where you fall
  • The healthy BMI range and the healthy weight for your height
  • All 8 WHO classes, from thinness to obese class III
  • A BMI chart by height
  • US units (ft, in, lb) and metric units (cm, kg)

Important to know

BMI may not suit athletes, pregnant women, older adults or children and teens (under 20), and the cut-offs can differ for some groups, such as people of Asian background. It is a screening measure, not a diagnosis. Talk to a doctor about your health.

Use this free BMI calculator, also called a body mass index calculator, to find your BMI and see what it means. It works for women and men, because the formula and the adult categories are the same for both, and you can enter your height and weight in US units (feet, inches, pounds) or metric units (cm, kg). You see your BMI, where it falls on a color scale, the healthy BMI range and the healthy weight for your height. Below the calculator are the WHO BMI categories and obesity classes, a BMI chart by height, and answers to common questions such as what BMI stands for. It is free and instant, and your numbers stay in your browser.

What is BMI?

BMI stands for Body Mass Index. It is a single number that compares your weight with your height. Doctors and health organizations use it as a quick first check to see whether a person's weight may be too low, healthy or too high for their height.

It is quick and free to work out, which is why it is so widely used. It is only a starting point though. It cannot tell you how healthy you are on its own.

The BMI formula explained

The formula divides your weight by your height squared.

Metric: BMI = weight (kg) ÷ height (m)²
US units: BMI = 703 × weight (lb) ÷ height (in)²

Example (metric): a person who weighs 70 kg and is 175 cm (1.75 m) tall has a BMI of 70 ÷ (1.75 × 1.75) = 70 ÷ 3.0625 = 22.9, which is in the healthy range.

Example (US units): a person who weighs 150 lb and is 5 ft 4 in (64 in) tall has a BMI of 703 × 150 ÷ (64 × 64) = 105,450 ÷ 4,096 = 25.7, which is in the overweight range.

BMI categories and obesity classes

These are the adult classes of the World Health Organization (WHO), which the CDC also uses for adults aged 20 and over. They are the same for women and men.

CategoryBMI
Severe thinnessBelow 16
Moderate thinness16 – 16.9
Mild thinness17 – 18.4
Healthy weight (normal)18.5 – 24.9
Overweight25 – 29.9
Obese class I30 – 34.9
Obese class II35 – 39.9
Obese class III40 or more

You may see the term morbid obesity. It is an older name for obese class III, a BMI of 40 or more, which the CDC calls class 3 or severe obesity.

What is a good BMI for women and men?

For adults the healthy range is the same for everyone: a BMI from 18.5 to 24.9. Women tend to carry more body fat than men at the same BMI, so the number is a rough guide, not a verdict. The BMI chart under the calculator shows the healthy weight for each height. At 5 ft 10 in, for example, a BMI from 18.5 to 24.9 is a weight of about 129 to 174 lb (58 to 79 kg).

BMI and body fat

BMI does not measure body fat. It only uses weight and height, so two people with the same BMI can have very different amounts of fat and muscle. To look at body fat directly, you can use the Body Fat Calculator.

What BMI cannot tell you

  • Muscle and fat. Muscle weighs more than fat, so a very muscular person can have a high BMI without carrying extra body fat.
  • Where fat is stored. Fat around the waist affects health differently from fat elsewhere, and BMI does not show this.
  • Age. Older adults often have more body fat at the same BMI.
  • Background. In 2004 a WHO expert group kept the standard cut-offs but added extra points at 23 and 27.5, because some Asian populations have a higher health risk at a lower BMI. Some countries use lower cut-offs, so it is worth asking your doctor which range suits you.
  • Children and teenagers. This calculator is for adults. For anyone under 20, BMI is compared with growth charts for their age and sex, and a doctor should interpret it.
  • Pregnancy. BMI is not a reliable guide during pregnancy.

If your result worries you, or you are planning to change your diet or exercise, talk to a doctor or a registered dietitian.

Sources

The rules, rates and ranges on this page come from these sources. Always check the current figures with the organization itself before you rely on them.

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Frequently Asked Questions

What does BMI stand for?

BMI stands for Body Mass Index. It is a number worked out from your weight and height, and it is used as a quick screening check of whether your weight may be low, healthy or high for your height.

What is a normal BMI?

For adults, a BMI from 18.5 to 24.9 is in the healthy (normal) weight range. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or more is obese.

What is a healthy BMI for women and for men?

The same: 18.5 to 24.9 for adults aged 20 and over, whether you are a woman or a man. The CDC applies the adult categories whatever a person's age, sex or race.

How do I calculate BMI?

Divide your weight in kilograms by your height in meters, squared. A person who weighs 70 kg and is 1.75 m tall has a BMI of 70 ÷ (1.75 × 1.75) = 70 ÷ 3.0625 = 22.9. The calculator does this for you.

How do I calculate BMI in pounds and inches?

Multiply your weight in pounds by 703, then divide by your height in inches squared. For example, 150 lb at 64 inches (5 ft 4 in) gives 703 × 150 ÷ 4,096 = 25.7. Choose the US units tab and enter feet, inches and pounds.

What are the BMI categories and obesity classes?

The WHO adult classes are: severe thinness below 16, moderate thinness 16 to 16.9, mild thinness 17 to 18.4, healthy weight 18.5 to 24.9, overweight 25 to 29.9, obese class I 30 to 34.9, obese class II 35 to 39.9, and obese class III 40 or more.

What BMI is morbidly obese?

"Morbid obesity" is an older term for obese class III, a BMI of 40 or more. The CDC calls it class 3, or severe, obesity. A doctor looks at more than BMI to judge a person's health.

Is BMI different for men and women?

No. The formula and the adult categories are the same. Women do tend to carry more body fat than men at the same BMI, which is one reason BMI is only a rough guide and works best alongside other measures.

What should I weigh for my height?

A healthy weight is one that gives a BMI from 18.5 to 24.9. At 5 ft 10 in that is about 129 to 174 lb (58 to 79 kg). The calculator shows the range for your own height, and the BMI chart by height lists other heights.

Is BMI accurate for athletes and muscular people?

Not always. BMI only uses weight and height, so a muscular person can have a high BMI with little body fat. Waist size or body fat percentage can give a clearer picture in that case.

Can I use this BMI calculator for children and teens?

No. It uses the adult categories, which are for ages 20 and over. For children and teens, BMI is compared with growth charts for their age and sex, and a doctor or nurse should read the result.

Is there a different BMI for Asian adults?

A WHO expert group in 2004 kept the standard cut-offs but added extra points at 23 and 27.5, because some Asian populations have a higher health risk at a lower BMI. Some countries use lower cut-offs, so ask your doctor which range suits you.

What is the difference between BMI and body fat?

BMI compares weight with height and does not measure fat. Body fat percentage is the share of your weight that is fat. Two people with the same BMI can have very different amounts of body fat. Try the Body Fat Calculator for an estimate.

Can I save, share or print my results?

Yes. After you press Calculate, use Copy link to get a link that opens the calculator with the same numbers, or Print for a clean printout. The numbers sit after the # in the link, a part of the address that browsers do not send to our server.

Are my numbers saved or shared?

No. The calculation happens in your browser, and the weight and height you type are not stored or sent to any server.