You're standing in the doctor's office. The nurse slides that cold metal weight across the scale, and you see the number. If you're 5'7", maybe you've been told your "perfect" number is 135 pounds. Or maybe 150. Honestly, most of those generic charts you see taped to clinic walls are based on data that's decades old.
It's frustrating.
Standard height-weight tables—the ones originally created by insurance companies like Metropolitan Life in the 1940s—don't care if you've been hitting the squat rack or if you have the bone structure of a Norse goddess. They just see a number. But for a woman 5 7 ideal weight isn't a single point on a line. It’s a range, and a wide one at that.
The medical establishment usually points toward the Body Mass Index (BMI). For a woman who is 5'7", the "normal" BMI range falls between 118 and 159 pounds.
That is a 41-pound gap.
Think about that. You could lose 40 pounds and still be "normal," or gain it and stay in the same category. It’s wild how much leeway there is, yet we often obsess over hitting one specific "goal weight" we had in high school.
The Math Behind the 5'7" Frame
Let's look at the actual numbers used by practitioners. Most doctors use the Devine Formula to calculate Ideal Body Weight (IBW), though it was originally meant for drug dosing, not for telling women how they should look in a swimsuit.
For a woman, the formula starts at 100 pounds for the first five feet of height. Then, you add five pounds for every inch over that.
$100 + (7 \times 5) = 135\text{ lbs}$.
Is 135 pounds realistic for everyone? Probably not. If you have a large frame or significant muscle mass, 135 might make you look gaunt and feel exhausted. On the flip side, the Hamwi formula—another old-school calculation—suggests 135 lbs but allows for a 10% range based on frame size. This means the woman 5 7 ideal weight could naturally sit anywhere from 121 to 148 pounds depending on whether your bones are "small," "medium," or "large."
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But how do you even know your frame size?
There’s a quick trick. Wrap your thumb and middle finger around your opposite wrist. If they overlap, you’re small-boned. If they just touch, you’re medium. If there’s a gap? You’ve got a large frame. It’s not laboratory-grade science, but it’s a lot more personal than a generic chart.
Why Muscle Changes the Entire Conversation
Muscle is dense. You’ve heard it before: "Muscle weighs more than fat." That’s technically wrong—a pound is a pound—but muscle occupies way less space.
Imagine two women. Both are 5'7". Both weigh 165 pounds.
Woman A is a distance runner with high body fat and low muscle tone. Woman B is a powerlifter with a 25% body fat percentage. Woman B might wear a size 6, while Woman A wears a size 12. Even though they are technically "overweight" by BMI standards (which caps at 159 lbs for this height), Woman B is metabolically much healthier.
This is where the "ideal weight" concept starts to crumble.
Dr. Nick Trefethen from Oxford University actually proposed a "New BMI" formula because he realized the standard version scales poorly for taller people. He argues that the traditional formula makes tall people think they are fatter than they are and short people think they are thinner. Under his math, the upper limit for a 5'7" woman would actually be slightly higher than the standard 159 lbs because of how volume increases with height.
Real Talk About Life Stages
Your "ideal" weight at 22 is rarely your "ideal" weight at 45.
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Perimenopause changes things. Bone density peaks in your 30s and then starts a slow slide. As estrogen levels fluctuate, the body naturally wants to store a bit more fat, particularly around the midsection. This isn't just "letting yourself go." It's biology.
Recent longitudinal studies have shown that for older adults, being on the slightly "heavier" side of the BMI scale (the 25-27 range) is actually linked to better longevity and recovery from illness. If you're 5'7" and 55 years old, 165 pounds might actually be "healthier" for you than 125 pounds, specifically because it provides a reserve against osteoporosis and frailty.
Beyond the Scale: What Actually Matters?
If we aren't using the scale as the ultimate judge, what are we using?
- Waist-to-Hip Ratio: This is a huge predictor of cardiovascular health. Take a tape measure. Measure the smallest part of your waist and the widest part of your hips. Divide the waist by the hip. For women, a ratio of 0.85 or lower is considered healthy. It tells you if you're carrying "visceral fat" (the dangerous kind around your organs) regardless of what the scale says.
- Blood Markers: Your A1C, your lipid panel, and your blood pressure. You can be 135 pounds and have "skinny fat" syndrome with high cholesterol and pre-diabetes. Conversely, you can be 170 pounds with perfect blood work.
- Energy and Strength: Can you carry your groceries up three flights of stairs? Can you hike? Do you wake up feeling like a zombie?
Honestly, the woman 5 7 ideal weight is whatever weight allows you to live a life that isn't dictated by food obsession. If maintaining 130 lbs requires you to eat 1,200 calories and obsess over every blueberry, it isn't your "ideal" weight. It's a prison.
Common Myths That Need to Die
There's this weird idea that every woman should aim for 115-125 pounds if they want to be "fit."
At 5'7", 115 pounds is a BMI of 18.0. That is clinically underweight.
Being underweight carries its own massive risks: hair loss, brittle bones, irregular periods (amenorrhea), and a weakened immune system. We’ve spent so long fighting the obesity epidemic that we sometimes forget that the "lower is better" mentality is equally dangerous.
Another myth? That you can "target" where the weight sits. You can't. Your genetics decide if that extra ten pounds goes to your hips or your belly. If you’re a 5'7" "pear shape," your ideal weight might look very different from an "apple shape" because of how fat distribution affects metabolic risk.
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Actionable Steps to Finding Your Personal Range
Forget the "perfect" number. Aim for a "health zone."
First, determine your frame size using the wrist method or by measuring your elbow breadth. This gives you permission to adjust those online calculators up or down by 10%.
Second, get a DEXA scan or a high-quality body composition analysis if you're curious about your muscle-to-fat ratio. Knowing you have 130 pounds of lean mass makes a 160-pound total weight look very different on paper.
Third, track your "non-scale victories" for a month. Note your sleep quality, your mood, and your strength levels.
The woman 5 7 ideal weight is a moving target. It shifts with your activity level, your age, and your hormonal health. If you are 5'7" and you're hovering between 140 and 155, you are likely in the sweet spot for most healthy, active women.
Stop fighting your skeleton. If you have broad shoulders and a wide pelvis, you were never meant to weigh 120 pounds. And that’s perfectly fine. Focus on the Waist-to-Height ratio—keep your waist measurement less than half your height. For a 5'7" woman (67 inches), that means keeping your waist under 33.5 inches. That’s a much better health marker than any number on a digital scale.
Move because you like it. Eat because you need fuel. The weight will eventually settle where it's supposed to be.