BMI Calculator

Work out your body mass index (BMI), see which adult category it falls in, and find the weight range that counts as a healthy BMI at your height. It's a screening number, not a diagnosis.

Your BMI
26.6
Overweight
Category (CDC, adults)
Overweight
Healthy-BMI weight for your height
111 lb to 150 lbBMI 18.5 to 24.9
Distance from that range
About 10 lb above the top of the range
  • For adults 20 and older. Children and teens (2 through 19) need a BMI-for-age percentile instead; use the CDC Child and Teen BMI Calculator.
  • BMI can't tell muscle from fat. Very muscular people can score "overweight" with little body fat, and older adults can score "healthy" while carrying more fat and less muscle.
  • If you have a South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background, the UK's NICE guideline uses lower thresholds: overweight from 23 and obesity from 27.5.
  • This is an estimate for information, not medical advice. A clinician will look at BMI alongside waist size, blood pressure, blood tests and history.

BMI categories at your height

CategoryBMIWeight
UnderweightBelow 18.5Under 111.2 lb
Healthy weight18.5 to 24.9111.2 to 149.6 lb
Overweight25.0 to 29.9150.2 to 179.7 lb
Obesity, class 130.0 to 34.9180.3 to 209.7 lb
Obesity, class 235.0 to 39.9210.3 to 239.8 lb
Obesity, class 340.0 and above240.4 lb or more

What BMI measures

Body mass index is your weight divided by the square of your height. It was designed for comparing groups of people, and doctors use it as a quick first screen because it needs only a scale and a tape measure. A higher BMI is linked, on average, to higher risk of type 2 diabetes, high blood pressure and heart disease.

For adults 20 and over, the CDC groups BMI into underweight (below 18.5), healthy weight (18.5 to under 25), overweight (25 to under 30) and obesity (30 or more). Obesity is split further into class 1 (30 to under 35), class 2 (35 to under 40) and class 3, sometimes called severe obesity (40 or more).

Where BMI gets it wrong

BMI doesn't distinguish fat, muscle and bone, and it says nothing about where you carry fat. Two people with the same BMI can have very different amounts of body fat and very different health risks.

Muscular people: athletes and people who lift weights can land in the "overweight" band with healthy body fat. NICE, the UK's health guideline body, says to interpret BMI with caution in adults with high muscle mass.

Older adults: muscle declines with age, so the same BMI can mean more body fat. NICE also advises caution in people 65 and over, noting a slightly higher BMI may be protective at older ages.

Ethnicity: a WHO expert consultation found that many Asian populations have higher risk of type 2 diabetes and heart disease at BMIs below 25. NICE recommends lower thresholds (overweight from 23, obesity from 27.5) for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background.

Children and teens: their BMI is compared with others of the same age and sex as a percentile, because body fat changes as they grow. This calculator doesn't do that; the CDC has a dedicated calculator for ages 2 through 19.

Using your result

Treat BMI as a prompt, not a verdict. If yours is outside the healthy range, a waist-to-height ratio is a useful second check, because fat around the middle carries more risk than fat elsewhere. NICE suggests using both for adults with a BMI under 35.

The healthy weight range shown is simply the weights that give a BMI of 18.5 to 24.9 at your height. It's wide on purpose. Pregnancy, some medical conditions and very high muscle mass all make BMI less useful, so talk to a clinician before setting a target.

The BMI formula

BMI = weight (kg) ÷ height (m)²BMI = 703 × weight (lb) ÷ height (in)²Weight for a given BMI = BMI × height (m)²
  • 703 converts pounds and inches to the metric result (the exact factor is about 703.07)
  • Height in meters = height in cm ÷ 100

Example

  1. An adult who is 5 ft 5 in (65 inches, 1.651 m) and weighs 160 lb (72.6 kg).
  2. BMI = 703 × 160 ÷ 65² = 112,480 ÷ 4,225 = 26.6.
  3. 26.6 is between 25 and 30, so the CDC category is overweight.
  4. Healthy range at this height: 18.5 × 1.651² = 50.4 kg (111 lb) up to 24.9 × 1.651² = 67.9 kg (150 lb).
  5. So this person is about 10 lb above the top of the healthy-BMI range.

Frequently asked questions

What is a healthy BMI for adults?

The CDC treats 18.5 to under 25 as a healthy weight for adults 20 and older. Below 18.5 is underweight, 25 to under 30 is overweight, and 30 or more is obesity.

Is BMI accurate for athletes?

Not very. BMI counts muscle the same as fat, so muscular people often score as overweight. A waist measurement or a body fat estimate gives a better picture for them.

Can I use this BMI calculator for my child?

No. For ages 2 through 19, BMI has to be compared with growth charts for the child's age and sex, giving a percentile. Use the CDC Child and Teen BMI Calculator.

Should BMI cutoffs be lower for Asian adults?

Often, yes. A WHO expert consultation found higher health risk at BMIs below 25 in many Asian populations, and NICE in the UK uses 23 for overweight and 27.5 for obesity for people of Asian, Middle Eastern, Black African and African-Caribbean backgrounds.

What is the BMI for 5 ft 5 in and 160 lb?

About 26.6, which is in the overweight range. The healthy-BMI weight range at 5 ft 5 in is about 111 to 150 lb.

Sources

Last reviewed for 2026. How we calculate.