A healthy weight for someone 5’9″ falls between roughly 128 and 168 pounds, based on the standard BMI range of 18.5 to 24.9. But that range is wide for a reason. Your ideal weight within it depends on your sex, age, muscle mass, and body composition. Here’s how to figure out where you personally should land.
The Healthy BMI Range at 5’9″
The CDC defines a healthy weight as a BMI between 18.5 and 24.9. For someone 5’9″, the National Heart, Lung, and Blood Institute’s BMI table maps out specific weights at each whole number:
- BMI 19: 128 lbs
- BMI 20: 135 lbs
- BMI 21: 142 lbs
- BMI 22: 149 lbs
- BMI 23: 155 lbs
- BMI 24: 162 lbs
Going above a BMI of 25 (around 169 lbs at this height) puts you in the “overweight” category, while 30 and above (roughly 203 lbs) crosses into obesity. Below 18.5 (about 125 lbs) is classified as underweight. These cutoffs aren’t arbitrary. They’re drawn from population-level data linking weight to disease risk, mortality, and metabolic health.
What the Clinical Formulas Say
Doctors have used several formulas over the decades to estimate “ideal body weight.” They were originally designed for medication dosing, not as personal weight goals, but they offer a useful ballpark. Running the numbers for a 5’9″ person:
- Devine formula: about 161 lbs for men, 151 lbs for women
- Hamwi formula: about 166 lbs for men, 151 lbs for women
- Miller formula: about 149 lbs for men, 141 lbs for women
These formulas consistently place men slightly higher than women at the same height, reflecting average differences in bone density and muscle mass. They also cluster around the middle of the BMI healthy range, which is a reasonable target for most people. None of them account for age, fitness level, or frame size, so treat them as starting points rather than hard targets.
Why BMI Doesn’t Tell the Whole Story
BMI divides your weight by your height squared. That’s it. It can’t distinguish between muscle and fat, and it doesn’t know where your body stores its weight. A 5’9″ person who strength trains seriously could weigh 185 pounds with a BMI of 27 (technically overweight) while carrying relatively little body fat. Meanwhile, someone at 155 pounds could have a normal BMI but carry excess fat around their midsection, which carries real metabolic risk.
Researchers have proposed alternatives like the fat-free mass index, which separates lean tissue from body fat and evaluates each independently. This kind of analysis identifies people who have excess muscle without excess fat, something BMI simply cannot do. If you’re physically active and muscular, BMI will overestimate your health risk. If you’re sedentary and carry most of your weight around your stomach, it may underestimate it.
Body Fat Percentage as a Better Marker
A 2025 study using US national survey data defined “overweight” as a body fat percentage of 25% or higher for men and 36% or higher for women. Obesity thresholds were 30% for men and 42% for women. These numbers give you a more direct measure of what’s actually happening in your body compared to stepping on a scale.
You can get a rough body fat estimate through tools like skinfold calipers, bioelectrical impedance scales (common in home bathroom scales), or more precise methods like a DEXA scan. If your scale weight seems high but your body fat percentage falls within a healthy range, you’re likely carrying more muscle than average, and the number on the scale matters less than it appears to.
Waist Size Matters More Than You Think
Where you carry fat is at least as important as how much of it you have. Fat stored around your organs (visceral fat) drives inflammation, insulin resistance, and cardiovascular risk far more than fat stored under the skin on your hips or thighs. The simplest way to gauge this: measure your waist and compare it to your height.
The NHS recommends keeping your waist circumference below half your height. At 5’9″ (69 inches), that means your waist should stay under about 34.5 inches. If you’re at a “healthy” BMI but your waist exceeds that number, you may still carry meaningful metabolic risk. If your BMI is slightly above 25 but your waist is well under half your height, that’s a reassuring sign.
How Age Changes the Picture
The standard BMI brackets were developed for adults 20 and older, but they don’t adjust for age. Research increasingly suggests they should. A study in the Annals of Geriatric Medicine and Research found that older adults with a BMI below 25 faced a higher risk of declining physical function, falls, loss of muscle strength, and malnutrition. The same study found the optimal BMI range for older adults was 25 to 35, with the sweet spot around 27 to 28 for men and 31 to 32 for women.
This is sometimes called the “obesity paradox”: in people over 65, carrying some extra weight appears to be protective. The likely explanation is that the extra weight acts as a reserve during illness, surgery, or the natural muscle loss that comes with aging. For a 5’9″ person over 65, this suggests a weight in the 170 to 190 range could be perfectly healthy, even though it falls outside the standard “normal” BMI window. The key is maintaining muscle mass and physical function, not chasing the same number you weighed at 25.
Health Risks of Staying Too Far Outside the Range
Carrying significant excess weight over time increases your risk of high blood pressure, type 2 diabetes, heart disease, stroke, many types of cancer, chronic kidney disease, fatty liver disease, joint problems like osteoarthritis, sleep apnea, and depression. These risks increase with both the amount of extra weight and how long you carry it. At 5’9″, moving from 170 pounds to 220 pounds doesn’t just shift your BMI category. It meaningfully raises your odds of developing these conditions over the following decades.
Being underweight carries its own set of risks: weakened immune function, bone loss, nutrient deficiencies, and hormonal disruption. For a 5’9″ person, staying consistently below 125 pounds warrants attention, particularly if it’s accompanied by fatigue, frequent illness, or menstrual irregularities in women.
Finding Your Personal Target
For most 5’9″ adults under 65, a weight between 135 and 168 pounds keeps you well within a healthy BMI. If you’re active and carry noticeable muscle, you can comfortably sit above that range without concern, especially if your waist stays under 34.5 inches and your body fat percentage is in a healthy zone (under 25% for men, under 36% for women). If you’re over 65, a slightly higher weight in the 170 to 190 range may actually serve you better.
No single number works for everyone at 5’9″. The scale is one data point. Combine it with your waist measurement, how you feel physically, your energy level, and if possible, a body fat estimate. Together, those give you a far more accurate picture than any formula on its own.