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What's a healthy BMI and waist size?

Check your BMI against the CDC adult ranges, including the lower cut points used for Asian Americans, and your waist against the NIH marks.

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Height
Weight
How to measure your waist
  1. Stand up and put a tape measure around your middle, just above your hip bones.4
  2. Keep the tape level and snug, but not digging into your skin.
  3. Measure just after you breathe out.4
Sex (sets which waist mark applies)
Background (sets which BMI cut points apply)

The CDC's adult ranges are for ages 20 and over.

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Your result

--.-BMI

Add your height and weight to see your result.

Your BMI will show on the scale above, with both sets of cut points side by side.

Why we say this

  1. BMI is weight in kg divided by height in meters, squared. Pounds and inches are converted first.9
  2. CDC adult ranges (ages 20+): healthy 18.5 to under 25, overweight 25 to under 30, obesity 30 or more (class 2 from 35, class 3 from 40).1
  3. American Diabetes Association, Asian American cut points (expert opinion): overweight from 23, obesity from 27.5; its surgery advice also moves 35 and 40 down to 32.5 and 37.5.2
  4. NIH waist marks: a waist of more than 35 inches (89 cm) for women or more than 40 inches (102 cm) for men increases the risk of heart disease and type 2 diabetes.4

Sources checked Oct 12, 2026. Full list below.

How this works

BMI (body mass index) is your weight in kg divided by your height in meters, squared.9 You can type pounds, feet and inches; we turn them into kg and cm first (1 pound = 0.4536 kg, 1 inch = 2.54 cm).

We compare your BMI with the CDC's adult ranges, which apply to adults 20 and older "regardless of age, sex, or race": 25 to under 30 is overweight and 30 or more is obesity.1 If you're Asian American, we also show the lower cut points the American Diabetes Association (ADA) uses in its diabetes care standards: overweight from 23 and obesity from 27.5.2

Why a second set? The ADA says that in Asian and Asian American people, the BMI cut points for overweight and obesity are lower "due to differences in body composition and cardiometabolic risk".2 The US Preventive Services Task Force also advises checking Asian Americans for diabetes from a lower BMI, 23 instead of 25.11 A WHO expert group had found in 2004 that many Asian people face higher diabetes and heart risk below a BMI of 25.5

Your waist adds what BMI misses: fat around the middle. The National Heart, Lung, and Blood Institute (NHLBI, part of the National Institutes of Health) says a waist of more than 35 inches for women or more than 40 inches for men increases the risk of heart disease and type 2 diabetes.4 That's why we ask your sex: it only changes which waist mark we use.

What it meansCDC (everyone)ADA, Asian American
HealthyBMI 18.5 to under 251BMI 18.5 to 22.92
OverweightBMI 25 to under 301BMI 23 to 27.42
ObesityBMI 30 or more1BMI 27.5 or more2
WaistMore than 35 in (89 cm) for women, more than 40 in (102 cm) for men raises risk4

What this can't tell you

  • How much of your weight is fat, muscle or bone.7
  • Whether extra weight is already affecting your health. That needs a checkup, not a calculator.6
  • Anything about children or teens under 20.3
  • Whether you need any treatment. Medicine labels look at BMI together with weight-related conditions, and a prescriber decides.10

Questions people ask

What are the CDC BMI ranges for adults?

For adults 20 and older, the CDC calls a BMI under 18.5 underweight, 18.5 to under 25 healthy, 25 to under 30 overweight and 30 or more obesity. Obesity is split into class 1 (30 to under 35), class 2 (35 to under 40) and class 3 (40 or more).1

Are BMI cut-offs lower for Asian Americans?

The CDC uses the same ranges for everyone.1 The American Diabetes Association uses lower cut points for Asian American people, based on expert opinion: overweight from a BMI of 23 and obesity from 27.5, because weight-related risks such as type 2 diabetes begin at a lower BMI. Its surgery advice also moves 35 and 40 down to 32.5 and 37.5.2 Our post on BMI cut-offs for Asian Americans goes into more detail.

What waist size is too big?

The National Heart, Lung, and Blood Institute (part of the NIH) says a waist of more than 35 inches for women or more than 40 inches for men increases the risk of heart disease and type 2 diabetes.4

Is BMI accurate if I'm muscular or older?

Not always. BMI can't tell fat from muscle or bone, and it doesn't show where fat sits.7 Muscular people can read as overweight, and older adults who have lost muscle can have a BMI that hides extra fat.8 Your waist size helps in both cases.

Does a high BMI mean I need a weight-loss medicine?

No. BMI and waist describe health risk. US medicine labels use BMI together with weight-related conditions, and a doctor or other licensed prescriber decides after looking at your whole health.10 Guide 3 covers all the options, from food and activity to medicines and surgery, and What BMI do you need for Wegovy? gives the label numbers.

Can I use this for my child or teenager?

No. The CDC's adult ranges are for people aged 20 and over. The CDC has a separate BMI calculator for children and teens aged 2 through 19, which compares them with others of the same age and sex.3

Weight and health Your options Should I consider a GLP-1? GLP-1 check: the FDA labels BMI cut-offs for Asian Americans Considering it for weight

Sources

  1. US Centers for Disease Control and Prevention (CDC). Adult BMI categories ("For adults 20 and older, BMI categories are based on a person's BMI regardless of age, sex, or race"; obesity classes 1 to 3). Page dated March 19, 2024. cdc.gov
  2. American Diabetes Association Professional Practice Committee. 8. Obesity and weight management for the prevention and treatment of type 2 diabetes: Standards of Care in Diabetes—2023. Diabetes Care 2023;46(Suppl 1):S128–S139. Table 8.1 (cut points for Asian American individuals, expert opinion) and recommendations 8.18–8.19. We read this edition in full; later editions were not open to us. doi:10.2337/dc23-S008
  3. CDC. Adult BMI calculator ("This BMI calculator is for adults 20 and older"; the Child and Teen BMI Calculator for ages 2 through 19). Page dated June 26, 2024. cdc.gov
  4. National Heart, Lung, and Blood Institute (NIH). Aim for a healthy weight: assessing your weight and health risk (how to measure your waist; "more than 35 inches for women or more than 40 inches for men increases your risk"). Updated December 11, 2025. nhlbi.nih.gov
  5. WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 2004;363:157–63. doi:10.1016/S0140-6736(03)15268-3
  6. Rubino F et al. Definition and diagnostic criteria of clinical obesity (Lancet Diabetes & Endocrinology Commission). Lancet Diabetes Endocrinol 2025;13:221–62. Declared interests: most of the 56 authors declare payments from Novo Nordisk, and many also from Eli Lilly (paper's own declaration). doi:10.1016/S2213-8587(24)00316-4
  7. CDC. About body mass index (BMI) ("BMI does not distinguish between fat, muscle, and bone mass"). Updated December 16, 2025. cdc.gov
  8. Batsis JA, Villareal DT. Sarcopenic obesity in older adults: aetiology, epidemiology and treatment strategies. Nat Rev Endocrinol 2018;14:513–37. doi:10.1038/s41574-018-0062-9
  9. Knowler WC et al.; Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346:393–403 (defines BMI as kg divided by meters squared). doi:10.1056/NEJMoa012512
  10. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Prescription medications to treat overweight and obesity ("a BMI of 30 or greater", or "a BMI of 27 or greater, and you have weight-related health problems"). Last reviewed June 2024. niddk.nih.gov
  11. US Preventive Services Task Force. Prediabetes and type 2 diabetes: screening. August 24, 2021 (screen "at a lower BMI (≥23) if the patient is Asian American"). uspreventiveservicestaskforce.org

Last checked Oct 12, 2026 · Next review due Jan 2027

How this tool was made. Built by the GLP Guidebook team from the sources above. It's general information, not medical advice. Talk to your doctor or another licensed prescriber before starting, stopping or changing any treatment. How we write