You know the feeling. You’re browsing an online shoe store, and you spot a gorgeous pair of heels or sneakers. The price is right, the style is perfect, but then you see it: size 38. Or size 39. Your heart sinks. You’ve worn a US size 8 for years, but what on earth is a 38? Is that a 7? A 9? Suddenly, that dream purchase feels like a risky gamble. You’re not alone—this confusion is one of the most common frustrations in women’s footwear, especially with the rise of international shopping and European brands.
The truth is, shoe sizing is a messy, global puzzle. Unlike clothing, where a medium is fairly consistent, shoes vary wildly by region, brand, and even the type of shoe. The numbers 38 and 39 are part of the European (EU) sizing system, which is the standard for most of the world outside of the US and UK. But here’s the kicker: there is no single, universal conversion. A size 38 in a high-end Italian pump might feel like a US 7.5, while the same size in a chunky sneaker from a sportswear giant could fit like a US 8. To make sense of it all, you need to stop thinking of sizes as fixed numbers and start thinking of them as measurements of your foot in millimeters.
The European System: A Simple Foundation
Let’s demystify the core of the problem. The European sizing system is surprisingly logical. It’s based on the length of the foot in centimeters, with a standard increment between sizes. Specifically, a size 38 typically corresponds to a foot length of about 24.0 to 24.5 centimeters (roughly 9.45 to 9.65 inches). A size 39 usually fits a foot length of about 24.5 to 25.0 centimeters (roughly 9.65 to 9.84 inches). So, the difference between a 38 and a 39 is just half a centimeter—about the width of your pinky fingernail. That’s not a lot of wiggle room, which is why getting the right fit is so critical.
Think of it this way: every shoe size is just a code for a specific length range. The European system is more straightforward than the US system because it doesn’t have the weird half-size gaps or the historical quirks (like the fact that US women’s sizing was originally based on men’s sizing). But here’s the first practical takeaway: a size 38 is not a “small” or “medium” in the abstract. It is a specific measurement. If your foot is exactly 24.3 cm long, a size 38 might be snug, while a size 39 might give you a little breathing room. Your goal isn’t to match a number—it’s to find the number that matches your foot.
Converting 38 and 39 to US and UK Sizes
Now, let’s tackle the conversions you’ll actually use. While there are official charts, remember that these are guidelines, not guarantees. For women’s shoes, a size 38 generally converts to a US size 7.5 to 8. A size 39 typically converts to a US size 8.5 to 9. In the UK system, a size 38 is roughly a UK 5 to 5.5, and a size 39 is about a UK 6 to 6.5. But here’s where the nuance comes in: these conversions are based on average foot shapes and standard lasts (the mold a shoe is built on). A shoe designed for a narrow European foot might feel tighter in the same US conversion than a shoe designed for a wider American foot.
Let’s break it down with a practical example. Imagine you normally wear a US women’s size 8. According to the chart, you’d likely fit a European size 38.5 or 39. But if you’re buying a pair of pointed-toe ballet flats, the toe box might be cramped in a 39, while a 38 could squeeze your toes. Conversely, if you’re buying a pair of athletic sneakers with a thick sock, you might want to size up to a 39 for extra room. The conversion is a starting point, not a final answer. Always check the brand’s specific size chart, and if they provide a “foot length in cm” column, use that as your primary guide.
Why the Same Size Feels Different Across Brands
This is the most common source of frustration. You buy a size 38 from Brand A, and it fits like a glove. You buy a size 38 from Brand B, and it feels like a boat or a vice. Why? It’s not because the sizing is random. It’s because brands use different “lasts”—the three-dimensional shape of the shoe’s interior. A last determines not just length, but also width, toe shape, arch height, and heel depth. A size 38 from a brand that specializes in narrow Italian shoes will be cut differently than a size 38 from a brand that caters to a wider American foot. Even within the same brand, a stiletto heel might be built on a narrower last than a chunky loafer.
There’s also the issue of “fit tolerance.” Some brands deliberately make their shoes a bit larger or smaller to accommodate different foot shapes or to create a specific aesthetic. For example, a minimalist sneaker brand might make their shoes slightly longer to give a “roomy” feel, while a luxury pump maker might make them slightly shorter to create a sleek, elongated silhouette. The result? A size 38 in one shoe might feel like a 37.5 in another. This is why reading customer reviews is invaluable. Look for comments like “I usually wear a 38, but I had to size up to a 39 in this style” or “Runs half a size small.” These real-world experiences are often more reliable than any conversion chart.
How to Measure Your Foot Like a Pro
If you want to nail your size 38 or 39 decision, you need to know your exact foot length. This isn’t complicated, but it’s often done wrong. Here’s a simple method you can do at home. Grab a piece of paper, a pen, and a ruler. Place the paper on a hard floor against a wall. Stand on the paper with your heel lightly touching the wall. (Don’t wear socks if you want a barefoot measurement, or wear the type of sock you’ll wear with the shoes.) Mark the longest point of your foot—usually the tip of your big toe or your second toe. Measure the distance from the edge of the paper (where the wall was) to your mark. Do this for both feet, because one foot is often slightly larger. Use the larger measurement.
Once you have your length in centimeters, compare it to the brand’s size chart. For a size 38, you want your foot length to be between 23.5 and 24.5 cm, depending on the brand’s specific range. For a size 39, aim for 24.5 to 25.5 cm. But don’t just match the number. Add a little wiggle room. The ideal fit should allow about 0.5 to 1 cm (roughly the width of your thumb) between your longest toe and the end of the shoe. This space prevents your toes from hitting the front when you walk, which can cause blisters and discomfort. If you’re between sizes, it’s almost always safer to size up, especially for closed-toe shoes or styles you’ll wear for long periods.
Practical Tips for Buying Shoes in Size 38 or 39
Armed with this knowledge, you can shop with confidence. Here are some actionable strategies to avoid the size 38/39 guessing game. First, always prioritize the brand’s own size chart over generic online converters. Many retailers now provide a “size guide” that includes foot length in centimeters. Use that as your primary reference. Second, pay attention to the shoe’s construction. Pointed toes, high heels, and rigid materials (like patent leather) often require a half-size up. Soft, stretchy materials (like suede or knit) can accommodate a more exact fit. Third, consider your foot width. European brands often run narrower than US brands. If you have wide feet, you might need to size up to a 39 even if your length suggests a 38, or look for styles labeled “wide” (often marked as “W” or “C/D”).
Another pro tip: use the “two-finger” test when trying on shoes. After putting on the shoe, try to slide your index finger behind your heel. If you can’t get your finger in, the shoe is too tight. If you can fit two fingers easily, it’s too loose. For size 38 and 39, this test is especially helpful because the half-centimeter difference can be subtle. Also, remember that leather and other natural materials often stretch with wear. A snug size 38 in leather might become comfortable after a few wears, while a synthetic material won’t give as much. If you’re unsure, order two sizes (like 38 and 39) from a retailer with a good return policy, and compare them at home. It’s a hassle, but it’s the surest way to find your perfect fit.
Final Recommendations for Size 38 and 39 Shoppers
So, what’s the bottom line? A size 38 is roughly a US 7.5 to 8, and a size 39 is roughly a US 8.5 to 9. But those numbers are just the beginning. The real secret to shoe shopping is understanding that your foot is a unique measurement, not a label. Don’t get attached to a specific number. Instead, get attached to how the shoe feels. When you’re shopping online, always check the brand’s size chart, read reviews for fit guidance, and measure your foot in centimeters. If you’re shopping in a store, try on both sizes if they’re available, and walk around a bit. Your feet swell during the day, so try shoes later in the afternoon when they’re at their largest.
Finally, embrace the fact that sizing is an art, not a science. You might be a size 38 in one brand and a 39 in another, and that’s perfectly normal. The goal isn’t to memorize a conversion; it’s to develop a feel for how different brands run. Over time, you’ll learn that a particular Italian label always runs small, while a certain American brand runs true to size. Until then, trust your measurements, be patient with returns, and remember: the perfect fit is worth the extra effort. Your feet will thank you, and you’ll never dread seeing “size 38” again.