There’s no single number you’re “supposed to” weigh. Your healthy weight depends on your height, sex, body composition, and overall metabolic health. But there are practical ways to estimate a reasonable range and, more importantly, to figure out whether your current weight is working well for your body.
A Quick Estimate Based on Height
The simplest starting point is a set of formulas doctors have used for decades to estimate ideal body weight. The most widely referenced is the Hamwi formula, which works like this: women start at 100 pounds for the first 5 feet of height and add 5 pounds for each additional inch. Men start at 106 pounds for 5 feet and add 6 pounds per inch. So a 5’6″ woman would get an estimate of about 130 pounds, while a 5’10” man would land around 166 pounds.
Other clinical formulas (Devine, Robinson, Miller) use slightly different math and can give results that vary by 10 to 15 pounds in either direction. That spread tells you something important: even among medical professionals, there’s no consensus on one magic number. These formulas were designed as rough guides, not verdicts. They don’t account for muscle mass, bone density, age, or ethnic background.
What BMI Tells You (and What It Doesn’t)
BMI, or body mass index, is probably the most familiar tool for categorizing weight. It divides your weight in kilograms by your height in meters squared. The CDC defines a healthy BMI as 18.5 to 24.9. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above falls into the obesity range.
For a 5’6″ person, a healthy BMI translates to roughly 115 to 154 pounds. For someone 5’10”, it’s about 129 to 174 pounds. That’s a wide window, and intentionally so. Two people at the same height can look completely different at the same weight depending on how much of that weight is muscle versus fat.
This is BMI’s biggest blind spot. It can’t distinguish between lean mass and fat mass, and it tells you nothing about where your body stores fat. A muscular person who strength trains regularly might register as “overweight” by BMI while carrying very little body fat. Meanwhile, someone with a normal BMI could have excess fat around their organs (a pattern sometimes called “normal weight obesity”) that raises their risk for heart disease and diabetes. The American Heart Association has specifically called out the limitations of relying on BMI alone, noting that it “fails to discriminate between adipose tissue depots in different anatomic regions.”
Better Ways to Gauge Your Weight
If you want a fuller picture, a few additional measurements help.
Waist-to-height ratio: Measure your waist at the belly button, then compare it to your height. The NHS recommends keeping your waist size to less than half your height. So if you’re 5’8″ (68 inches), your waist should ideally stay below 34 inches. This simple check captures something BMI misses: how much fat you carry around your midsection, which is the type most strongly linked to cardiovascular and metabolic problems.
Body fat percentage: A 2025 study using US national survey data defined “overweight” as body fat of 25% or more for men and 36% or more for women. “Obesity” started at 30% for men and 42% for women. You can get a rough body fat estimate from smart scales at home, though DEXA scans at imaging centers are far more accurate. Harvard Health notes there’s no universally agreed-upon ideal range, but these thresholds give you a reasonable benchmark.
Waist circumference on its own: For women, a waist above 35 inches is generally associated with higher metabolic risk. For men, the threshold is 40 inches. This is especially useful if your BMI is in the “normal” range but you carry weight around your middle.
Why Some People Are Healthy at Higher Weights
Researchers have spent years studying a phenomenon called “metabolically healthy obesity,” where a person’s BMI qualifies as obese but their blood work and vital signs look normal. The concept is real but complicated: more than 30 different definitions have been used across studies, and there’s no universal standard for identifying it.
Most commonly, metabolic health is assessed by checking five markers: blood pressure, fasting blood sugar, triglycerides, HDL cholesterol, and waist circumference. If someone has at most one of these in an abnormal range, they’re often classified as metabolically healthy regardless of their BMI. Some researchers add insulin sensitivity and liver fat content to the criteria for a more complete picture.
The takeaway isn’t that weight doesn’t matter. It’s that weight is one data point among several. A person at 180 pounds with normal blood pressure, healthy blood sugar, and good cholesterol numbers is in a very different situation from someone at 180 pounds with three or four of those markers out of range. The number on the scale doesn’t capture that distinction.
How to Find Your Personal Target
Rather than chasing a single number, it helps to think in ranges and patterns. Start with the BMI-based weight range for your height as a rough bracket. Then narrow it with what you know about your body. If you carry significant muscle mass, the upper end of a healthy BMI (or even slightly above it) may be perfectly fine. If you’re sedentary and carry most of your weight around your waist, even a “normal” BMI might not tell the whole story.
Your own weight history matters too. Many people have a range where their body seems to settle naturally when they’re eating well, sleeping enough, and staying active. This “set point” differs from person to person and tends to shift upward with age, partly because muscle mass declines about 3 to 8 percent per decade after age 30 if you don’t actively work to maintain it.
If you want a concrete number to orient around, the Hamwi formula gives you a midpoint, and adding or subtracting 10 percent creates a reasonable range. For a 5’6″ woman, that’s roughly 117 to 143 pounds. For a 5’10” man, about 149 to 183 pounds. These aren’t rules. They’re starting coordinates. What your blood work says, how you feel, how you move, and where your body stores fat all matter at least as much as what the scale reads.