Reverse BMI Calculator

How reverse BMI works

Standard BMI works forward: enter weight and height, get a number. Reverse BMI works backward: enter the BMI you want to hit and your fixed height, and it tells you the weight that corresponds. The math is simple, weight = BMI × height² (in metric), but the use case is powerful, it turns an abstract health classification into a concrete target on the scale.

Why work backward? Doctors and fitness coaches usually frame healthy weight as a BMI range (CDC's is 18.5–24.9 for adults 20 and older). But that range hides the actual pounds you'd need on the scale. A 5'8" person at BMI 22 weighs 145 lb. At BMI 24.9, they weigh 164 lb. Knowing the difference, 19 pounds, lets you plan in tangible terms: how many pounds to lose, how many weeks at 1 lb a week, how realistic the goal is.

Reverse BMI is also useful for athletes who want to peak at a specific competition weight (boxing, wrestling, rowing weight classes), people recovering from illness who need to regain weight to a safe range, and anyone preparing for a doctor visit who wants to understand the numbers their physician will discuss.

Target weight by height (BMI 22)

BMI 22 sits near the middle of CDC's healthy range (18.5 to under 25), which makes it a convenient example; it isn't an official target. Here's what BMI 22 looks like at common heights, with the whole pounds inside the healthy range:

Notice that the "healthy" weight range widens as height increases. A 5'0" adult has a 33 lb healthy range (95–128 lb), while a 6'4" adult has a 53 lb range (152–205 lb). That's because BMI scales with the square of height, so the same BMI gap covers more pounds when you're taller.

Setting a realistic weight goal

If your current weight puts you in the overweight or obesity BMI category, a nearer target can be easier to plan for than the bottom of the healthy range. A 220 lb adult at 5'9" (BMI 32.5) trying to hit BMI 22 (149 lb) needs to lose 71 lb, which takes about 16 months at 1 lb a week, the slow end of the 1 to 2 pounds a week that CDC describes as gradual and steady. Aiming for BMI 27 first (183 lb) is a 37 lb loss, about 17% of body weight, in roughly 9 months; the second leg from 27 → 22 can be a separate phase.

CDC says that if you are not at a healthy weight, even modest weight loss can help improve your blood pressure, cholesterol, and blood sugar; its example is a 5% loss, which for someone who weighs 200 pounds is 10 pounds. The National Heart, Lung, and Blood Institute says a loss of 3% to 5% can lower triglycerides and glucose. You don't have to hit a textbook BMI to benefit.

If your current weight is already in the healthy range and you're changing your body composition, the scale can barely move while you lose fat and gain muscle. The scale tells you BMI; a body fat percentage measurement (see our body fat calculator) tells you whether the change is happening in the right tissue.

BMI limitations to remember

BMI is a screening tool, not an individual diagnosis. CDC calls it a quick, safe and reliable screening measure and says it is moderately to strongly associated with other measures of body fat. It takes only two numbers, but it has real blind spots:

• Muscle vs fat: A muscular 5'10" athlete at 200 lb has a BMI of 28.7, in the overweight range, however little body fat they carry. CDC notes that BMI cannot distinguish between fat, muscle, and bone.
• Body shape: BMI can't show where fat is carried. Waist measures, including waist-to-hip ratio, capture this; the National Heart, Lung, and Blood Institute says a waist of more than 40 inches for men or 35 inches for women increases the risk of heart disease and type 2 diabetes.
• Ethnicity: NIDDK's guidance on who to screen for diabetes treats a BMI of 23 or more as overweight for Asian Americans, lower than the standard 25.
• Age: CDC applies the adult categories to everyone 20 and older, regardless of age. Children and teens are assessed with BMI-for-age percentiles instead.
• Pregnancy: BMI isn't a guide to weight during pregnancy; CDC bases recommended pregnancy weight gain on BMI before pregnancy.

For most adults, BMI gives a useful starting point. CDC advises considering it alongside other factors, such as a physical exam, lab results, and health behaviors; a waist measurement is one of the simplest to add.

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