Running Shoe Sizing: Should You Go a Half Size Up?

There’s a common piece of advice that floats around advising that you should buy running shoes a half size bigger, but what does this really mean? 

Should you buy running shoes a half size bigger than your normal shoe size? Should you buy running shoes a half size bigger than the size your foot measures at the shoe store? 

Should you buy running shoes a half size bigger than the size that feels right at the store when you’re trying them on?

Moreover, is this advice sound? Should you size up your running shoes?

In this article, we will discuss if you should buy running shoes a half size bigger, what this means, and how to ensure your running shoes fit correctly.

In this guide, we will cover: 

• What Size Running Shoes Do I Need?

• How Should Running Shoes Fit?

• Should You Buy Running Shoes a Half Size Bigger?

• Why You Should Buy Running Shoes a Half Size Bigger

• Should You Buy Running Shoes a Full Size Bigger?

• Signs That Your Running Shoes Are Too Small

Let’s dive in! 

What Size Running Shoes Do I Need?

Most running shoe experts, or fit experts at specialty running stores, say that one of the most common mistakes beginner runners and even seasoned runners make when buying running shoes is not having their feet properly measured by a store associate to kick off the process.

Even though all runners, including beginners, probably have some other pair of sneakers with a legible size marker still present, the shape and size of our feet do change as we get older.

The small intrinsic muscles in the feet stretch out over time, allowing the bones and tissues of the feet to spread ever so slightly. This causes our feet to get bigger as we age, particularly if you carry excess weight, are on your feet a lot, and don’t actively perform foot exercises to strengthen these little muscles.

For this reason, getting your feet properly measured by an expert is the first step to getting running shoes that fit.

The device used to measure foot size, known as a Brannock device, measures the length of your foot from the back of your heel to the tip of your longest toe, as well as the width of your foot and the length of your arch.

Arch length is important because you want the arch of the running shoe to match up with your anatomical arch. There will be a certain amount of give and support in this area of the shoe and you want that to coincide with your true arch.

Note here that a common error that runners make when buying running shoes, which ultimately leads to buying shoes that are too small, is that they measure their own feet at the shoe store. When doing so, many runners erroneously look at the length or shoe size indicated on the Brannock device at the tip of their big toe, or first toe.

Unfortunately, this is not necessarily your longest toe. For many runners, the second toe, or “index finger toe” is actually longer than the big toe. Failing to use your longest toe as a reference to how big your running shoes need to be will result in shoes that are too short in the length.

How Should Running Shoes Fit?

Although we all have an intuitive idea of how a running shoe should feel if it fits, some runners aren’t actually sure how running shoes should fit.

Typically, you want a running shoe to feel fairly snug in the heel and midfoot—as if lightly hugging or holding your foot, while the forefoot area should be roomier. 

There should be a decent amount of wiggle room for your toes to accommodate the natural foot splay (lengthening and widening of the foot) that occurs when you land and push off with your foot.

In terms of proper running shoe length, most experts recommend having at least a thumbnail’s of width between your longest toe and the end of the shoe.

Should You Buy Running Shoes a Half Size Bigger?

First things first. What do people mean when they say you should buy running shoes a half size bigger? A half size bigger than what?

Generally speaking, getting running shoes a half size bigger means a half size bigger than your normal street shoe size, though it can also mean you should buy running shoes a half size bigger than the shoe size your foot measures, since these are usually one in the same in terms of size.

The whole point of measuring your foot with a Brannock device is to get the accurate shoe size you need. Thus, for pretty much all types of shoes other than running shoes, the size of your shoes should match the measured foot size.

Here, running shoes are the exception-hence the advice to size up your running shoes a half size.

Why You Should Buy Running Shoes a Half Size Bigger

So, should you buy running shoes a half size bigger? Let’s see what the experts have to say.

The main reason shoe experts recommend sizing up your running shoes a half size is to ensure you have ample length in the shoe to accommodate natural swelling that occurs in the feet over the course of the day and while you run.

Additionally, when your foot makes contact with the ground, particularly when you push off from the forefoot, the ball of your foot widens or flattens a bit and the toes extend forward, or lengthen. 

Wearing running shoes a half size bigger than your normal shoe size helps ensure you have adequate room for this natural foot splay and the mild swelling.

Should You Buy Running Shoes a Full Size Bigger?

Some runners find that buying running shoes a full size larger is actually the way to go.

Interestingly, a half size is only one-eighth of an inch (0.318 cm) longer in length. This is a very small increase. 

As such, some runners actually do better wearing running shoes a full size bigger than their normal shoe size instead of a half size bigger. 

Runners who tend to experience more significant foot swelling over the course of the day, as well as runners who do the majority of their training in the afternoon or evening when feet are at their largest, should consider buying running shoes a whole size bigger than their regular shoe size.

Finally, some running shoe brands tend to run small. For these shoes, you’ll probably need to size up at least a full size.

Signs That Your Running Shoes Are Too Small

You can usually tell if your running shoes are too small or too short in the length because they simply won’t feel comfortable, especially towards the end of the run. Aside from being uncomfortable, there are a few additional signs that it’s time for you to size up your running shoes.

Signs that your running shoes are too small include the following:

• Pain or discomfort 

• Lack of wiggle room in the toes

• Black or bruised toenails

• Blisters or calluses on the tips of your toes

• Blisters under your toenails

• Bent toes or hammertoes 

Some runners are self-conscious or reticent about buying running shoes that are actually big enough and fit properly, as if a smaller size is somehow “better” or more dainty in a good way. 

If you have an emotional hang up surrounding shoe size, try to put your ego—or whatever it is—aside and buy running shoes that fit properly no matter what size is printed on the tongue.

Numerical size doesn’t matter in the least bit, and your feet will be healthier and happier if you choose running shoes that actually fit. After reviewing our information, if you’re asking yourself, should you buy running shoes a half size bigger, you probably should!

For some more guidance on choosing running shoes, when to change up your running shoes, and a running shoes rotation, check out our variety of articles on these subjects:

How To Pick The Right Running Shoes: Our Complete Guide

How To Break In New Running Shoes Guide

Running Shoe Rotation: Rotate Your Shoes For Better Running