You’ve found the perfect pair of heels online—a sleek, classic design from a European brand that’s been on your wishlist for months. You click “Add to Cart,” but then you freeze. The size chart looks like a foreign language. It says “38,” and you’re a solid US size 7.5. Is that a match? A size 8? Or are you about to order something that will fit like a clown shoe?

This moment of confusion is incredibly common. International sizing can feel like a secret code, and women’s shoe sizes are some of the trickiest to crack. If you’ve ever stared at a size 38 tag and wondered where it lands on the American scale, you’re not alone. Let’s demystify this number once and for all.

The Short Answer: What Is a Women’s 38 in US Sizes?

Let’s cut to the chase. In the vast majority of cases, a women’s European size 38 converts to a US size 7.5. Think of it as the sweet spot for medium-width feet. However, because shoe sizing isn’t an exact science, it can also sometimes fit a US size 7 or a US size 8, depending on the brand, the shoe style, and the last (the mold the shoe is built on).

Here’s a quick reference for the most common conversions around the 38 mark:

  • EU 37 = US 6.5
  • EU 37.5 = US 7
  • EU 38 = US 7.5
  • EU 38.5 = US 8
  • EU 39 = US 8.5

So, if you wear a US 7.5 in most brands, a size 38 is your golden ticket. But as with all good things in life, there’s a little more nuance to it.

Why the Confusion? The Difference Between Sizing Systems

To understand why a size 38 isn’t always a perfect 7.5, it helps to know how the two systems actually work. They don’t just use different numbers; they use different units of measurement and different starting points.

The European System (Mondopoint)
European shoe sizes are generally based on the length of the last, measured in Paris points. One Paris point equals two-thirds of a centimeter. This system is relatively linear, meaning the difference between a size 37 and a 38 is a consistent 0.66 cm. It’s a metric, logical system that doesn’t account for width in the sizing number itself. A size 38 is a size 38, whether it’s a ballet flat or a hiking boot.

The US System
The American system is a bit more… artistic. It’s based on barleycorns, an old English unit of measurement (about one-third of an inch). A US women’s size starts at a baseline and adds increments. The difference between sizes is roughly 0.21 inches (or about 0.53 cm). The kicker? US sizing also often builds in a “comfort” allowance or varies dramatically between athletic shoes, heels, and boots. A US size 7.5 in one brand might feel completely different from a US size 7.5 in another.

Because the European increment is slightly larger than the US increment, your foot doesn’t always land perfectly on a whole number. That’s why you’ll sometimes see half sizes in European shoes, like a 38.5, which is designed to bridge the gap.

The Real-World Factors That Change the Fit

Knowing the conversion number is just the first step. The real art of shopping for international shoes lies in understanding these three variables:

1. Brand and Country of Origin
An Italian size 38 from Prada may fit very differently from a German size 38 from Birkenstock. Italian and French brands often run slightly narrow and true to the length. German and Scandinavian brands might run a touch wider or longer, as they are often designed for a more generous foot shape. Always look at the specific brand’s size guide, not just a generic chart.

2. Shoe Type Matters
A size 38 in a pointed-toe pump will feel tighter in the toe box than a size 38 in a round-toe sneaker. For closed-toe shoes, especially heels, you might want to go up half a size (to a 38.5) if you are a solid US 7.5. For sandals or open-toe styles, the length is less critical, and a 38 might be perfect. For boots, consider the thickness of the socks you plan to wear. If you want to wear thick wool socks, a 38 might be too snug, and a 39 could be the better choice.

3. Your Unique Foot Shape
Are your feet narrow, wide, or high-volume? Do you have a high instep? The European system doesn’t always build width into the main size number (though some brands use letters like “M” for medium or “W” for wide). A size 38 is designed for a foot that is roughly 9.25 inches (23.5 cm) long. If your feet are wider than average, you may find that a 38 feels too tight across the ball of your foot, even if the length is perfect. In that case, you might need to size up to a 39 for the width, or look for brands that offer wide fits.

How to Find Your Perfect Fit Without Trying On

Since you can’t try on the shoe before you buy it (unless you’re in the store), you need to become a detective. Here is a step-by-step strategy to nail the size 38 conversion every time.

Step 1: Measure Your Foot in Centimeters
This is the most reliable method. Forget the US size for a moment. Grab a piece of paper, a pen, and a ruler. Trace your foot while standing (your foot spreads when you bear weight). Measure the length from the tip of your longest toe to the back of your heel. Do this for both feet—one is almost always slightly larger. Use the longer measurement.

Step 2: Match Your CM to the EU Size
A size 38 is generally designed for a foot that measures 24.0 cm to 24.5 cm (9.45 to 9.65 inches). If your foot is exactly 24.0 cm, a 38 should fit well. If your foot is 24.5 cm, you are on the upper edge, and a 38.5 or 39 might be safer, especially for closed-toe shoes.

Step 3: Check the Brand’s Specific “Last”
Many high-end brands have a signature “last” or shape. Look at reviews. Do people say, “I’m a US 7.5, and this 38 was too big”? Or “I’m a US 7, and this 38 fit perfectly”? Reviews are your best friend for understanding if a brand runs large or small.

Step 4: Consider the Return Policy
When in doubt, order two sizes. Order the 38 and the 39 (or the 38 and 38.5 if available). Try them on at home with the socks you intend to wear. Walk around on a carpet. Keep the pair that fits best and return the other. This is the most foolproof method for online shopping.

Practical Tips for Buying Shoes in Size 38

Now that you’re armed with knowledge, here is some final, actionable advice for your next shopping spree.

  • For heels and pumps: If you are a solid US 7.5, a 38 is usually correct. If you are between sizes (like a 7.5 wide or a narrow 8), consider a 38.5. Your toes will thank you.
  • For sneakers and athletic shoes: Many athletic brands (like Nike, Adidas) have their own specific conversion. Nike often runs a half size small. A women’s US 7.5 in Nike is often a EU 38.5 or even a 39. Always check the brand’s specific chart for running shoes.
  • For boots: If you plan to wear thick socks, size up to a 39. If you wear thin tights, stick with a 38. Leather boots will also stretch slightly over time, so a snug-but-not-painful fit is ideal.
  • For sandals and flip-flops: Fit is less critical, but you don’t want your heel hanging off the back. A 38 is usually perfect for a US 7.5 foot.
  • Don’t ignore half sizes: A 38.5 is a real, useful size. It bridges the gap between a US 7.5 and an 8. If you find yourself saying, “I’m a 7.5, but sometimes an 8 fits better,” the 38.5 is your sweet spot.

Final Thoughts

So, what is a women’s size 38 shoe in US sizes? It is a US 7.5—most of the time. But more importantly, it is a number that represents a foot length of roughly 24.0 to 24.5 centimeters. The next time you see that magic number on a pair of beautiful Italian boots or French flats, don’t panic. You now have the tools to decode it, measure against your own foot, and make a confident purchase. Happy shopping, and may your size 38s always fit like they were made for you.