Should you buy running shoes a size bigger? The answer isn't simple. Learn why bigger isn't always better, how to find the perfect fit, and what really causes foot pain while running.
Running Shoes Size: How to Find the Right Fit for Your Feet
When you buy running shoes size, the numerical measurement that determines how well a shoe fits your foot. Also known as running shoe fit, it’s not just about matching your foot to a number—it’s about matching your movement, your stride, and your foot shape to the right structure. Too tight, and you risk blisters, numb toes, or plantar fasciitis. Too loose, and you lose control, risk ankle rolls, or develop black toenails. It’s not a guess. It’s science.
Your foot isn’t static. It expands when you run. Your left foot might be half a size bigger than your right. And most people buy shoes based on what they wore five years ago—when their feet were younger, less swollen, and less worn out. That’s why so many runners get hurt. foot measurement, the process of accurately measuring length, width, and arch height to determine proper shoe fit isn’t something you do once. Do it every time you shop, especially after long runs or if you’ve gained or lost weight. And don’t trust store sizes blindly. A size 9 in Nike might be a size 8.5 in Asics. The brand doesn’t matter as much as how your foot feels inside the shoe.
running footwear, the category of shoes designed specifically for forward motion, impact absorption, and foot support during running isn’t just about cushioning. It’s about stability, toe box room, heel lock, and flexibility. Look for shoes that let your toes wiggle, don’t pinch your midfoot, and don’t slide when you push off. Try them on at the end of the day, when your feet are biggest. Wear the same socks you run in. Walk, jog, even jump a little in the store. If your heel slips or your big toe hits the front, keep looking.
And don’t ignore width. Most people only think about length. But if your foot is wide and you squeeze into a narrow shoe, you’ll get bunions, neuromas, or just constant discomfort. Brands like New Balance and Brooks offer wide and extra-wide options. If you’ve ever had to cut open the side of a shoe? That’s your body telling you it’s too tight.
There’s no magic formula. No app that replaces your own feel. But if you pay attention—measure your feet, test the fit, listen to your body—you’ll avoid the most common mistake runners make: buying shoes that don’t fit right. The right size doesn’t mean you’ll run faster. But it means you’ll run longer. Without pain. Without stopping. Without giving up.
Below, you’ll find real advice from runners who’ve been there—how to measure your foot properly, which brands run true to size, why your shoe size might change after a few years of running, and what to do when your favorite model gets discontinued. No fluff. Just what works.