This BMI calculator gives your body mass index (BMI) and CDC category, then shows how it compares with the criteria on the FDA labels of Wegovy® and Zepbound®. BMI is the first number clinicians look at when discussing weight-loss medication, but it is only a starting point.
BMI calculator & GLP-1 criteria check
Calculate your BMI and see how it compares with the criteria on the FDA labels of Wegovy® and Zepbound® for adults.
For adults. The CDC adult BMI categories apply from age 20; this tool is not designed for children or teens. The FDA labels of Wegovy® and Zepbound® (chronic weight management) cover adults with a BMI of 30 or more, or 27 or more with at least one weight-related condition. Meeting these criteria doesn't mean a medication is right for you: only a licensed clinician who knows your health history can decide. BMI doesn't measure body fat directly and is less accurate for some people (for example very muscular people, older adults, some ethnic groups).
Not for everyone: these medications are not used during pregnancy or breastfeeding, and are not appropriate for people with a personal or family history of medullary thyroid cancer or MEN2. Tell your clinician if you have had pancreatitis, gallbladder, kidney or eye (diabetic retinopathy) problems, an eating disorder, or take insulin or other diabetes medicines. Zepbound can make birth-control pills less effective.
How the BMI calculator works
BMI is your weight divided by your height squared. In US units, the calculator uses the standard formula: 703 × weight (lb) ÷ height (in)². For example, someone who is 5 ft 6 in (66 inches) and weighs 210 lb has a BMI of about 33.9.
It then applies two references:
| Reference | What it uses |
|---|---|
| CDC adult BMI categories | Underweight below 18.5, healthy weight 18.5 to under 25, overweight 25 to under 30, obesity 30 or more (class 1: 30 to under 35, class 2: 35 to under 40, class 3: 40 or more) |
| FDA label criteria for chronic weight management | Adults with a BMI of 30 or more, or 27 or more with at least one weight-related condition, as written in the Wegovy® prescribing information |
The checkbox tells the tool whether a clinician has diagnosed a weight-related condition, such as high blood pressure, type 2 diabetes, high cholesterol, sleep apnea or heart disease. Nothing you enter is sent or saved.
How to read your result
- BMI 30 or more: the FDA labels of Wegovy® and Zepbound® cover adults in this range for chronic weight management.
- BMI 27 to 29.9: included in the label only with at least one weight-related condition.
- Below 27: these medications are not labeled for you; a clinician can discuss other approaches.
- Below 18.5: weight loss is not recommended. If you are worried about your weight or eating, please talk to a doctor.
Matching the criteria is only the first step: a clinician must check your medical history, current medications and contraindications. The safety note under the calculator lists who these medications are not for.
Limits of BMI
BMI does not measure body fat directly. It can overestimate fat in very muscular people and is less accurate for some older adults and some ethnic groups. The CDC says it should be considered with other factors when assessing someone’s health, and its adult categories apply from age 20. This tool is not designed for children or teens.
Frequently asked questions
What BMI do you need for Wegovy or Zepbound?
Both FDA labels require a BMI of 30 or more, or 27 or more if you also have a condition linked to weight, such as high blood pressure or type 2 diabetes. Meeting that threshold is not enough on its own: a clinician still decides, based on your full health history.
Is BMI 27 overweight or obese?
A BMI of 27 is in the CDC’s overweight range (25 to under 30). Obesity starts at 30. At 27, the weight-loss labels of Wegovy® and Zepbound® only apply if you also have a weight-related condition.
Is BMI calculated differently for women and men?
No. The CDC uses the same adult BMI categories for women and men, whatever their age or race, from age 20. The formula is the same too. What differs between people is how well BMI reflects body fat, which is why a clinician looks at more than this number.
Can I get a GLP-1 if my BMI is under 27?
These medications are not FDA-approved for weight management below that threshold. Some are approved for other conditions, such as type 2 diabetes, where different criteria apply. Talk to a clinician about what fits your situation.