Selecting the correct shoe size can be somewhat of an enigma. When I buy shoes from a store, I might fit into any size from 10.5 to 13. These days I tend only to make my own shoes (perks of being a shoemaker), but before I knew how I always felt perplexed as to how my size could vary so much between brands and styles of shoes.
When I went to purchase my first pair of shoes on my own, I did what I learned from my parents. I put one on, laced it up, walked around for a moment, and then pressed my thumb into the toe box to see if my toes had about a quarter inch of space. No more, no less.
When I started to learn to make shoes, and learned to measure people’s feet, I found out this was all wrong.
For one, no one has perfectly symmetrical feet. I have measured lots of people. In one instance only, have I measured a person with the exact same foot measurements. It was so alarming that I had to measure them again. When I did, I found that they were slightly different. That made me feel insecure so I measured them yet again, still getting the slight difference. I measured one more time, getting the difference again, and that’s what I went with.
If you only put one shoe on at the store, you may never notice that one of your feet is larger than the other. If you do put both on, you may just think the shoes aren’t the same. The more reasonable conclusion is that you, in fact, have feet which are not symmetrical. That is okay! That is normal! Shoemakers do not have a problem with it. It does however, cause a problem for the buyer if the buyer is purchasing pre-made, factory shoes. The buyer doesn’t get any choices, and is powerless to change that. They just have to go with what’s there, or not. The system is set up for a quick sale, not to serve the individual buyer (you), best.
When purchasing, you should always try on both shoes. While the pre-made shoes can’t be changed, you can at least find the middle ground, so that one is not too big or too little. Typically your larger foot will correspond to which hand you favor. So if you’re right handed, typically your right foot will be larger. It just works that way most of the time. I think because you also favor that leg, so the foot gets more action and thus grows larger to accommodate. Start with the larger foot. If the shoe is too small for it you can’t wear that size of the shoe you’re trying on, not comfortably.
Second, all feet have a different shape, and so do shoes. Some shoes have really long toe boxes. Some shoes are wide in the waist, yet narrow in the heel, in which case your foot will pop out as you walk, unless your feet fit that shape.
The reason shoes have different shapes is because we all want different styles, and looks, whether those styles and look serve a purpose, or are simply for aesthetic. I have large feet, yet I have short toes (a thing my wife will not let me forget) comparatively. If I pick out shoes from the store that have a long toe box, it will be easy for me to assume they are too big for my feet, since there will be an inch of wasted space between my large toe and the end of the shoe. For this reason, pressing my thumb into the toe box to find my toes, becomes useless due to the intended design of the shoes. If I try a smaller size, my toes may fit to the end, but the rest of my foot may not sit in the correct place to wear the shoes comfortably.
The better way to make sure a shoe fits the length of your foot is first to set your foot back into the heel and tie them. You don’t need to kick your foot into the heel, just set it. Once the shoe is tied, stand up and try to feel where the ball of your foot sits within the shoe. There is usually a sweet spot in there where the arch ends, and the ball can rest comfortably. The only thing you need to make sure of in the toe, is that you have at least a quarter inch of space that when you put your weight on your foot it has room to splay (or widen when there is weight on it). Otherwise, how much room you have in the toe makes no difference as long as the ball fits correctly.
Once you find that the shoe actually fits in the right place, you now need to make sure you have enough room in the heel and in the waist. If they are too tight and the store does not offer differing widths, you may have to increase the size by a half and see if your foot still fits well in the ball.
By the way: Whole sizes and half sizes are a little misleading in the way we express them. A size 10 for example, is not an inch smaller than a size 11. It is half an inch smaller. And a 10.5 is only a quarter of an inch smaller than a size 11.
Lastly, since all types of shoes, athletic, hiking, dress, work, etc… serve different purposes, you will need to make sure you have in your mind what purpose the shoes will serve for you. If you’re buying work boots, but only plan to wear them casually, then its’ perfectly acceptable to buy them a little snug so that they will more sleek when you are wearing them. If you’re buying work boots for work, they are usually already a little on the big side so that your feet have plenty of room when your weight is on them throughout the day. Otherwise your toes might cramp and your feet feel worse inside the shoe than if you were working barefooted.
Final note: Shoe sizes at the store have little to do with what your actual foot size is. When you come in to see me, I will not even ask for your shoe size. I will simply measure each of your feet in five places, and send you on your way. If you have very atypical feet I will discuss with you about altering the lasts. Otherwise I will choose a last that best conforms to your feet.
If its not your thing to get measured, no sweat! All of my footwear is offered in normal US shoe sizes. Think what size you'd wear in boots and choose that. I will likely ask you once you order whether or not you find that your feet are wide or narrow. And hey, if you get them and they are not a good fit, you have 30 days to return them in new condition and I will either stretch them or make you a new pair. If you're not satisfied with that I will refund your money upon return.
See also: How to select high quality shoes from the store, for some great tips on avoiding shoddy craftsmanship.