BMI Calculator

Divide weight in kilograms by height in meters squared. For 70 kg at 1.75 m: 70 / (1.75 x 1.75) = 22.9. In US units, divide weight in pounds by height in inches squared, then multiply by 703. For 150 lb at 66 inches: 150 / (66 x 66) x 703 = 24.2.

For adults, below 18.5 is underweight, 18.5 to 24.9 is the healthy range, 25 to 29.9 is overweight, and 30 or above is obesity. The same cut-offs apply to men and women aged 20 and older.

The screening cutoffs are the same for women and men: 18.5 to 24.9 is labeled the healthy range. BMI does not account for body composition, which differs between women and men, so the number is a starting point rather than a target. A clinician can say what the range means for you specifically.

BMI is a quick screen, not a precise health measure. Because it uses only height and weight, it can classify muscular people as overweight and can miss excess body fat in others. Its meaning also varies by age, frame, and ethnicity. Clinicians use it alongside other measurements, not on its own.

Muscle weighs more than fat by volume, and BMI cannot tell the two apart. A muscular person can land in the overweight range with low body fat. That is a known limit of the index, and one reason a clinician reads BMI alongside waist size, body composition, and history instead of on its own.

It depends on height, because the divisor is height squared. At 5 ft 4 in one BMI point is about 5.8 lb, at 5 ft 6 in about 6.2 lb, and at 5 ft 8 in about 6.6 lb. Day-to-day fluctuations of a pound or two barely move it, which is why the trend over weeks matters more than any single reading.

No. The adult categories are not used the same way during pregnancy, when weight gain is expected and tracked differently. Prenatal weight guidance comes from your clinician, not a screening index.

The formula is the same, but the interpretation is different: for ages 2 to 19, BMI is compared against age- and sex-specific growth percentiles rather than the fixed adult cutoffs. This calculator uses the adult categories, so it applies to adults 20 and older.

No. BMI is a screening index, not a prescription or an eligibility decision. Whether any treatment is appropriate is a clinical judgment your doctor makes using your full health picture, not a number from a calculator.

The 18.5 to 24.9 range is labeled the healthy weight range for population screening. It is a reference band, not a personal goal or a guarantee of health. Someone inside or outside it can be healthy, so ask a clinician what the number means for you.

Where weight sits. Two people with the same BMI can carry weight very differently, and fat around the middle carries more health risk than the index alone shows. That is why clinical screening often pairs BMI with a waist measurement instead of relying on either number by itself.

The FDA labels for weight-loss GLP-1 medications describe use at a BMI of 30 or higher, or 27 or higher with at least one weight-related condition such as type 2 diabetes, high blood pressure, or sleep apnea. Insurers often apply their own, sometimes stricter, rules. Those are label facts, not an eligibility check: whether any medication fits you is a decision your clinician makes from your full history, never something a calculator decides.

The adult cutoffs are the same from age 20 up; what changes is interpretation. In older adults, muscle loss can hide body-composition changes the index cannot see, and some research suggests slightly higher BMIs read differently later in life. The categories stay fixed; the conversation with a clinician is what adjusts.

Take the BMI points above 24.9 and multiply by the pounds-per-point for your height, about 5.8 lb at 5 ft 4 in, 6.2 lb at 5 ft 6 in, and 6.6 lb at 5 ft 8 in. From a BMI of 29 at 5 ft 6 in, that is roughly 25 pounds. The explore slider under the scale does this arithmetic live: drag to any weight and watch where it lands for your height. To turn a change into percentages and milestone dates, the weight-loss percentage calculator and timeline calculator pick up where BMI stops.

No. The calculator runs entirely in your browser. Your height and weight are not added to the URL, not sent to MeAgain, and not stored after you leave the page.