You're standing on the scale. It's 7:00 AM. You're 5'6". The little digital numbers flicker, and suddenly your entire mood for the day is decided by a piece of plastic and glass. We’ve all been there. But honestly, the obsession with finding the "perfect" number for a woman who is 167.6 centimeters tall has become a bit of a national pastime, and frankly, it’s mostly based on math from the 1830s.
That's not a typo.
The BMI—the thing your doctor probably uses to tell you if you're "normal"—was invented by a Belgian mathematician named Lambert Adolphe Jacques Quetelet. He wasn't a doctor. He wasn't even studying health. He was just looking at the "average man." So, when we talk about the ideal weight for 5'6 female, we are often fighting against a ghost in the machine.
The Traditional Range vs. Reality
If you open a medical textbook, the standard answer is pretty rigid. For a woman standing 5 feet 6 inches, the "healthy" Body Mass Index (BMI) range is typically 18.5 to 24.9. In actual pounds, that translates to a window of 115 to 154 pounds.
That is a massive gap.
A 39-pound difference is the weight of a medium-sized Border Collie. It’s the difference between someone who looks like a marathon runner and someone who looks like a powerlifter. This is where the "ideal" starts to break down because it doesn't account for what those pounds actually consist of. If you have dense bones and a lot of muscle, you might weigh 160 pounds and have a lower body fat percentage than someone who weighs 125 pounds but has very little muscle mass.
Doctors sometimes call this "skinny fat," though the more professional term is Metabolically Obese Normal Weight (MONW). It basically means your weight is "perfect" on paper, but your internal health—like your cholesterol or insulin sensitivity—is actually struggling.
What About the Hamwi Method?
There's this other old-school formula called the Hamwi method. It’s been used by dietitians for decades to calculate "Ideal Body Weight" (IBW). It says a woman should weigh 100 pounds for the first 5 feet of height and then add 5 pounds for every inch after that.
For you, that’s 100 + (6 x 5).
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130 pounds. Give or take 10% for frame size. So, if you have a "large frame," the formula says 143 is your sweet spot. If you’re "small-boned," it’s 117. It’s simple. It’s clean. And it’s almost entirely arbitrary because it ignores age, race, and activity level.
Why Your "Frame" Actually Matters
You’ve probably heard someone say they are "big-boned" and rolled your eyes. But it’s a real thing. It’s called skeletal frame size.
If you want to get nerdy about it, wrap your thumb and middle finger around your wrist. If they overlap, you’re small-framed. If they just touch, you’re medium. If they don’t meet? Large frame. This isn't just an excuse to weigh more; it's physics. A person with a larger skeleton naturally carries more connective tissue and muscle just to move that skeleton around.
For a 5'6" woman, a large-framed person will almost always feel "starved" at 125 pounds, whereas a small-framed person might feel heavy at 145.
We also have to talk about the "menopause shift." As women age, particularly as they move through perimenopause and into menopause, the body naturally redistributes fat. Research published in The Journal of Clinical Endocrinology & Metabolism suggests that a slightly higher BMI in older age can actually be protective against things like osteoporosis and certain types of frailty. In that context, "ideal" might actually mean being at the higher end of the 150s.
The Muscle Factor and the 150-Pound Myth
I know a woman who is 5'6" and weighs 158 pounds. According to the CDC, she is technically "overweight."
She also deadlifts 250 pounds and has a resting heart rate of 54.
She is the picture of health.
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Muscle is roughly 15-20% more dense than fat. It takes up less space. This is why you can stay the exact same weight but drop two dress sizes if you start lifting weights. When you’re hunting for the ideal weight for 5'6 female, you’re really hunting for an ideal body composition.
Instead of the scale, many modern experts like Dr. Gabrielle Lyon (who focuses on muscle-centric medicine) suggest looking at your strength-to-weight ratio. Can you do a push-up? Can you carry your own groceries up three flights of stairs? Those are better indicators of whether your weight is "ideal" than a number on a dial.
Waist-to-Hip Ratio: A Better Metric?
If you hate the BMI, you’re in good company. Many researchers now prefer the Waist-to-Hip Ratio (WHR).
It’s pretty straightforward. Measure the smallest part of your waist and the widest part of your hips. Divide the waist by the hips. For women, a ratio of 0.85 or lower is generally linked to better cardiovascular health. This matters because "visceral fat"—the stuff that sits around your organs—is the real killer. You can weigh 130 pounds, but if all that weight is in your midsection, your health risks are actually higher than a woman who weighs 160 but carries it in her legs and hips.
Real World Examples
Let's look at three different women, all 5'6".
- The Endurance Athlete: She weighs 122 pounds. She runs 30 miles a week. She’s lean, but her bone density might be a concern if she doesn't eat enough.
- The Corporate Executive: She weighs 148 pounds. She does yoga twice a week and walks the dog. She’s right in the middle of the "healthy" range. Her blood pressure is perfect.
- The CrossFit Enthusiast: She weighs 162 pounds. She has a lot of visible muscle. By BMI standards, she’s "overweight," but her body fat percentage is 22%, which is very athletic.
Which one is at the "ideal" weight? All of them.
The idea that there is one single number is just a marketing tactic used to sell tea detoxes and "shred" programs. It doesn't exist. Your "happy weight" is usually the one where your blood markers (glucose, lipids, etc.) are stable, and you have enough energy to live your life without feeling like you're constantly in a battle with your refrigerator.
Common Misconceptions About 5'6" Bodies
People think that because 5'6" is slightly taller than the average American woman (who is about 5'4"), they have more "room" to play with. That’s sort of true, but it also means the stakes for joint health are higher.
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There's also the "Weight Set Point" theory. Your body has a range it wants to be in. If you’ve been 145 pounds for ten years and you suddenly try to force yourself down to 125 because a chart told you to, your hormones (specifically ghrelin and leptin) are going to scream at you. Your metabolism will likely slow down to compensate. This is why 95% of people who lose weight on restrictive diets gain it back. They are fighting their body's biological "safe zone."
The Role of Ethnicity
It is also worth noting that the "ideal" weight isn't colorblind.
Research has shown that the risks for Type 2 diabetes and heart disease start at a lower BMI for Asian women compared to Caucasian women. Conversely, some studies suggest that African American women may have higher bone density and muscle mass, meaning a slightly higher weight might be perfectly healthy. The "one size fits all" approach of the 140-pound ideal is, frankly, outdated and culturally narrow.
What You Should Actually Measure
If you're going to ignore the scale—or at least stop obsessing over it—what should you look at?
- Waist Circumference: Generally, staying under 35 inches is the gold standard for reducing disease risk.
- Blood Sugar (A1C): This tells you how your body handles carbs regardless of your weight.
- Sleep Quality: If you're too heavy for your frame, sleep apnea becomes a risk. If you're too thin, insomnia often kicks in.
- Energy Levels: Do you crash at 3:00 PM? That’s a sign your nutrition or weight might be off-balance.
Actionable Steps for Finding Your Balance
Stop looking for a magic number and start looking for a "performance" range.
First, get a DEXA scan if you’re really curious. It’s the only way to truly know how much of your 5'6" frame is muscle, bone, and fat. It’s way more useful than a bathroom scale.
Second, focus on "adding" rather than "subtracting." Instead of trying to lose 10 pounds to hit some 135-pound "ideal," try adding 5 pounds of muscle. You might end up weighing more, but you'll look leaner and feel significantly stronger.
Third, track your "non-scale victories." How do your jeans fit? How is your skin? Are you able to lift your carry-on bag into the overhead bin without asking for help? These are the real metrics of a body that is at its ideal weight.
Final thought: Your weight is a data point, not a destiny. If you're 5'6" and you're 155 pounds but you feel like a superhero, don't let a chart from the 1800s tell you that you're failing.
Next Steps for Your Health Journey:
- Measure your waist-to-hip ratio this morning to get a baseline of your metabolic health.
- Schedule a basic blood panel to check your fasting glucose and cholesterol; these numbers matter infinitely more than the scale.
- Audit your strength by seeing how many bodyweight squats you can do with good form; prioritize building muscle over shedding pounds.
- Throw away or hide the scale for two weeks and focus entirely on how your food affects your mood and energy levels.