What Size is Women’s 40 Shoe

Women’s Size 40: The Short Answer

A women’s size 40 shoe is a European size. In US sizing, it typically converts to a women’s size 9.5 or 10. In UK sizing, it is usually a size 7 or 7.5. The exact fit depends on the brand and the width of your foot.

This is not a one-size-fits-all answer. Some brands run narrow. Others run wide. You might be a solid US 9.5 in one shoe and a perfect US 10 in another. Always check the specific brand’s size chart before you order.

European vs. US vs. UK: The Conversion Chart

Here is the basic breakdown for a women’s Euro size 40. Use this as your starting point. It is your anchor for shopping, but not the final word.

• US Women’s: 9.5 (most common) or 10 (for wider feet)
• UK Women’s: 7
• Japan / CM: 25.0 or 25.5 cm

If you usually wear a US 9.5 in sneakers like Nike or Adidas, you will likely need a Euro 40. If you wear a US 10 in dress shoes, the Euro 40 is often a better bet. The difference is usually about half a centimeter in length. That is not much, but it is enough to cause blisters or heel slippage.

Why Size 40 Is Tricky: Brand Variations

The biggest mistake people make is assuming all size 40s are identical. They are not. A size 40 in a running shoe is not the same as a size 40 in a high heel.

Sneakers and athletic shoes (like New Balance or Asics) often run true to size. They are built on a wider last. If you are a 9.5, a 40 usually fits with your normal socks. European luxury brands (like Gucci or Prada) often run narrow. In those, you might need a 40.5 or 41 if you have a medium or wide foot. Boots and clogs (like Birkenstock or Dr. Martens) have their own sizing quirks. Birkenstock runs large. You often size down a full size, meaning a US 9.5 might wear a 39 in Birkenstock.

Always read the reviews. Look for comments about whether the shoe runs small, large, or true. That real-world feedback is more valuable than any chart.

How to Measure Your Foot at Home

Do not guess. Measure your foot. It takes two minutes and saves you from return shipping fees.

1. Tape a piece of paper to the floor against a wall.
2. Stand on the paper with your heel touching the wall. Put your weight on that foot.
3. Mark the longest point of your toe on the paper.
4. Measure the distance from the edge of the paper to your mark in centimeters.
5. If the measurement is 25.0 cm, you are a size 40. If it is 25.5 cm, you are right on the border of 40 and 41.

Measure both feet. Most people have one foot slightly larger. Buy for the bigger foot. If your measurement is 25.3 cm, you have a choice. For closed-toe shoes, go with the 40. For pointy-toe shoes or high heels, go up to the 41. Your toes need extra room in those.

What to Do When You Are Between Sizes

Being between a 39.5 and a 40 is common. So is being between a 40 and a 41. Here is how to decide.

Think about the shoe’s material. Leather stretches with wear. A snug size 40 in full-grain leather will mold to your foot. Suede also gives a little but less than smooth leather. Canvas and mesh do not stretch much. If the shoe is made of stiff synthetic material, size up. If it is soft leather, stay true to size.

Think about the shoe’s purpose. For running shoes, you want a thumb’s width of space between your longest toe and the end of the shoe. If you are between sizes, go up. For dress shoes or loafers, you want a snug fit so they do not slip off. If you are between sizes, go down or stay true.

One final tip: shop in the afternoon. Your feet swell during the day. Shoes bought in the morning may feel tight by 5 PM.

How to Fix a Slightly Loose or Tight Size 40

If you already bought the shoes and they are close but not perfect, you have options. Do not just live with the pain.

If the size 40 is too big: Use a heel grip. It sticks to the back of the shoe and stops your heel from slipping. For loafers, add a cushioned insole. This takes up volume and makes the shoe feel more secure. You can also wear thicker socks with sneakers or boots.

If the size 40 is too tight: For leather shoes, use a shoe stretcher. You insert it overnight with stretching spray. It works best on full-grain leather. For suede, take them to a cobbler. They have professional stretchers that handle delicate materials. Do not try to stretch canvas or mesh. It will not work. You need to exchange those for a size 41.

Mink oil can soften stiff leather boots. Apply a small amount and wear them around the house for an hour. The leather will relax and stretch slightly.