Free Health Tool
Adult BMI Calculator
Calculate your Body Mass Index and find out what your number means for your weight and overall health.
Your BMI
<18.5 Healthy
18.5–24.9 Overweight
25–29.9 Obese
30+
What is BMI?
Body mass index (BMI) is a widely used tool for estimating body fat based on your height and weight. While it doesn't directly measure body fat, BMI can help identify whether you are underweight, within a healthy weight range, or living with overweight or obesity. Healthcare providers frequently use BMI as a screening measure, not a diagnostic one.
BMI categories
| Category | BMI Range | What it may mean |
|---|---|---|
| Underweight | Below 18.5 | May indicate nutritional deficiency or other health concerns |
| Healthy Weight | 18.5 – 24.9 | Associated with lower risk of weight-related health issues |
| Overweight | 25 – 29.9 | May increase risk of certain cardiovascular and metabolic conditions |
| Obesity Class I | 30 – 34.9 | Higher risk of diabetes, heart disease, and sleep apnea |
| Obesity Class II | 35 – 39.9 | Significantly elevated risk; provider guidance recommended |
| Obesity Class III | 40+ | Highest risk category; medical intervention often recommended |
How is BMI calculated?
BMI is calculated by dividing your weight in kilograms by your height in meters squared (kg/m²).
Metric: BMI = weight (kg) ÷ height² (m²)
Imperial: BMI = [weight (lbs) ÷ height² (in²)] × 703
For example, a person who is 5'7" (170 cm) and weighs 154 lbs (70 kg) has a BMI of approximately 24.1 — in the healthy range.
Frequently asked questions
Once you calculate your BMI, it will fall into one of the standard categories: underweight, normal weight, overweight, or obesity. These categories offer a general sense of how your weight may relate to your risk for certain health conditions. Think of your BMI as a starting point — not a verdict.
BMI doesn't distinguish between muscle and fat, nor does it account for fat distribution — particularly visceral fat, which is more strongly associated with cardiometabolic risk. It also doesn't consider factors like age, sex, ethnicity, or lifestyle habits. Athletes often have a higher BMI due to muscle mass while still being very healthy.
Think of your BMI range as a starting point — not a verdict. On its own, BMI can't tell you everything about your health, but it can offer a useful frame of reference for deeper conversations with your healthcare provider. If your BMI falls outside the healthy range, it may be worth exploring treatment options.
Yes. Clinically-proven treatments like Semaglutide (GLP-1) and Tirzepatide have been shown to support significant weight loss in adults with a BMI of 27 or higher when combined with lifestyle changes. These are compounded prescription medications that require a licensed provider evaluation. Explore our RX Store to learn more about available treatments.
