When shoes don't fit, most women do the same thing: they change the size. They go up a half. They try a full size down. They order three sizes and return two. The size number becomes the variable they keep adjusting—because it's the variable they know how to change.
But here's what most women aren't told: size and width are two separate measurements, and for a very large percentage of women, width is the one that's actually wrong. You can find your perfect size in a shoe and still have it fit terribly if the width doesn't match your foot. And you can try every size in the lineup without ever solving the problem—because you're adjusting the wrong dimension.
What Size Actually Measures—and What It Doesn't
Shoe size measures length. That's it. When a size 8 fits and a size 8.5 doesn't, you're getting information about the length of your foot relative to that specific last.
Size tells you nothing about:
• How wide your foot is across the ball
• How deep your foot is (instep height)
• How much volume your foot takes up in the toe box
• Whether the heel cup will hold you securely
All of those things are determined by width—and by the specific last a shoe is built on. Two size 8 shoes from two different brands can fit completely differently, even if both are labeled B width, because the last shapes vary. Not sure what width letters like B, D, or AA actually mean? Our guide to shoe width letters explains the full system. Width letters give you a starting point; last construction determines the outcome.
The Most Common Shoe Fit Problems—and Their Real Cause
Problem: "My heel slips when I walk."
What most women do: Size down.
The real issue: The shoe is too wide for their foot, so there's not enough structure holding the heel in place. Sizing down makes the toe box shorter but doesn't change the width relationship. The heel still slips—and now the toes are cramped too.
The fix: Try a narrower width. A properly fitted narrow shoe holds the heel naturally because the entire shoe is proportioned for a slimmer foot. See the 5 signs you have narrow feet.
Problem: "The toe box feels tight and my feet hurt after an hour."
What most women do: Size up.
The real issue: The shoe is too narrow for their foot. Sizing up gives more room in the toe area temporarily, but it also moves the ball of the foot forward relative to the shoe's flex point—which creates a new set of fit problems. The underlying issue (insufficient width) is still there.
The fix: Try a wider width. A D or EE shoe in the correct length gives the toes and forefoot the room they actually need without throwing off the rest of the fit. See the 5 signs you have wide feet.
Problem: "I always have to break shoes in."
What most women assume: That's just how shoes work.
The reality: A shoe in the right length and width should feel good—or at least neutral—from the first wear. It may take some time to fully conform to your foot, but it shouldn't hurt. Consistent break-in pain is almost always a sign of a width mismatch.
The fix: Identify whether you're sizing or widthing correctly. Start with the Complete Women's Shoe Width Guide if you're not sure where to begin.
→ Read: The Complete Women's Shoe Width Guide
Problem: "I buy the same size everywhere but it fits differently in every brand."
The real issue: Sizing isn't standardized across brands—and neither is width. But the variance you feel across brands is often about last width, not just length. A brand that runs narrow (which many European and fashion brands do) will feel tight to someone with a standard or wide foot even in her "correct" size.
The fix: When trying a new brand, check whether they offer multiple widths and whether their standard aligns with your foot. A brand that takes width seriously will typically publish a detailed size and width guide. Learn what width letters mean and how to use them when shopping.
Why the Industry Defaults to Size—and Why That's a Problem for You
The shoe industry has conditioned consumers to think about fit almost entirely in terms of size. It's a simpler system to sell around—one number per customer rather than a number and a letter. And most mass-market brands only produce in a single width anyway, so there's no width option to offer.
The result is a fitting room culture where women are taught to try size variations when something doesn't fit, because that's the only lever they're given. Half up. Half down. Different brand. Same problem.
For women at either end of the width spectrum—narrow or wide—this system simply doesn't work. No amount of size adjustment will compensate for a fundamental width mismatch. These women often conclude that their feet are "difficult" or that comfortable dress shoes just don't exist for them. Neither is true.
When Sizing Up Is Actually the Right Answer
To be fair: there are legitimate reasons to size up. If a shoe runs short in its last (which some styles do), sizing up compensates for that. If your feet swell significantly during the day and you need afternoon fit to take priority, that's also a real factor.
But there's a key difference between sizing up to account for length variation and sizing up to compensate for a width problem. The former is a legitimate fit adjustment. The latter is a workaround that creates new problems—and never fully solves the original one.
Not sure if your issue is size or width? Our guide on When to Size Up vs. Change Width walks through exactly how to tell the difference.
→ Read: When to Size Up vs. Change Width
How to Know If Width Is Your Problem
Ask yourself these questions:
• Have you tried multiple sizes in a style without finding one that feels right?
• Do shoes feel fine in length but wrong in some other way you can't describe?
• Do your feet get tired quickly in dress shoes even when the size is correct?
• Do you consistently size down to prevent heel slip—but then feel toe pressure? You may have narrow feet.
• Do you consistently size up for toe room—but then feel like the shoe is too long? You may have wide feet.
• Have you ever been measured for width? (If not, now is a good time.)
If you answered yes to two or more of those, width is very likely the variable you've been missing.
What Happens When You Get the Width Right
Women who find their correct width for the first time often describe it the same way: "I didn't know shoes could feel like this." Not because the shoes are unusually luxurious—but because the shoe is simply doing what a shoe is supposed to do: holding the foot securely, distributing weight evenly, and allowing natural movement without pinching, slipping, or compensating.
The break-in period shrinks or disappears entirely. End-of-day foot pain becomes a thing of the past. And styles that used to feel impossible—heels, pointed toes, strappy sandals—start to actually work.
That's not magic. That's just fit.
• Shop Marmi's Narrow Collection
• Shop Marmi's Wide Collection
• Shop All Widths at Marmi