BMI Calculator

Q: Is BMI an accurate measure of health?

BMI is a quick screening tool, not a full picture of health. It does not measure body fat directly or show where weight is carried. A provider looks at BMI together with other factors such as blood pressure, blood sugar and family history.

Q: What BMI do I need to qualify for medical weight loss?

Prolong Health's online evaluation is for adults 18 to 74 with a BMI of 27 or higher, or 25 or higher with a weight-related condition. A licensed provider decides whether treatment is appropriate, and completing an intake does not mean a prescription will be issued.

Q: Does this calculator save my height and weight?

No. The calculation happens in your browser, and your numbers are not sent to or stored by Prolong Health.

Q: Can I have a healthy BMI and still have health risks?

Yes. BMI alone cannot show how much fat you carry, where it is distributed, or how your blood sugar, blood pressure and cholesterol look. These are best reviewed with a provider.

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Underweight< 18.5

Healthy Weight18.5 – 24.9

Overweight25 – 29.9

Obesity30+

How the BMI calculator works

How it works

Body mass index (BMI) compares your weight with your height. It is your weight in kilograms divided by your height in meters squared. In pounds and inches, the formula is 703 times your weight in pounds, divided by your height in inches squared. This calculator does that math for you in your browser.

How to read your result

For adults, the standard BMI ranges are:

Under 18.5: underweight
18.5 to 24.9: healthy weight
25 to 29.9: overweight
30 or higher: obesity

BMI is a screening number, not a measurement of health. It does not measure body fat directly, and it cannot tell muscle from fat or show where weight is carried on your body. Very muscular people can have a high BMI without excess body fat, and BMI can read differently depending on age, sex and background.

When to talk to a provider

If your BMI is in the overweight or obesity range, or if you are concerned about your weight regardless of the number, a licensed provider can look at your full health picture, including blood pressure, blood sugar, cholesterol, family history and any weight-related conditions. A BMI in the healthy range does not rule out health concerns, and an elevated BMI does not mean a medical problem on its own.

Provider-guided weight management can include nutrition, activity, behavior support and, for some adults, prescription medication. Prolong Health offers an online evaluation for adults 18 to 74 with a BMI of 27 or higher, or 25 or higher with a weight-related condition. A provider decides whether treatment is appropriate, and not everyone qualifies.

This calculator provides an estimate for general education. It is not a diagnosis, and it does not determine whether you are eligible for any treatment. Your results are calculated in your browser and are not sent to or stored by Prolong Health.

Frequently asked questions

Is BMI an accurate measure of health?

BMI is a quick screening tool, not a full picture of health. It does not measure body fat directly or show where weight is carried. A provider looks at BMI together with other factors such as blood pressure, blood sugar and family history.

What BMI do I need to qualify for medical weight loss?

Does this calculator save my height and weight?

Can I have a healthy BMI and still have health risks?

Sources and further reading

BMI is calculated from height and weight only — it doesn't directly measure body composition and may not accurately reflect health for people with high muscle mass, pregnant women, children, older adults, or those with certain health conditions. BMI is a screening tool, not a diagnosis, and this calculator does not determine eligibility for any treatment. Whether a treatment is appropriate for you is something only a licensed provider can determine after reviewing your full health history.