Know your size. It’s best to have your foot's length, width and arch length measured on a specially calibrated fit device at REI. Foot volume, another key to good fit, must be assessed by a specialist at a store.
You can also measure your foot length and use REI.com sizing charts to find your size. Double-check length later by pulling the insoles out of the boots and standing on them; you should have a thumb’s width of space between your longest toe and the end of the insole.
Try on boots at the end of the day. Your feet normally swell a bit during the day’s activities and will be at their largest then. This helps you avoid buying boots that are too small.
If you wear orthotics, bring them along. They impact the fit of a boot.
Wear appropriate socks. Familiar socks help you more quickly assess the fit and feel of new footwear. Make sure the thickness of the socks matches what you intend to wear. And on the trail, go with synthetic rather than slow-drying cotton socks, which are more likely to give you blisters. Shop REI's selection of hiking socks.
Spend some time in the boots. Take a stroll through the store. Walk up and down stairs. Find an inclined surface and walk on it.
Fit issues to share with your footwear specialist: You don't want to feel odd bumps or seams, or pinching in the forefoot, nor toes hitting the end of the boot when it's on an incline. If the boots are laced firmly and you still feel space above the top of your foot, then the volume of the boot is wrong.
When shopping online, consider a brand you’ve worn before. Most boot companies tend to use a consistent foot model over time, so the fit is likely to be similar.
Change your knot strategy: How you lace your boots can change how they fit. See our article on Lacing Tips to improve your fit.
Consider aftermarket insoles (a.k.a. footbeds). Insoles come in models that can enhance comfort, support or fit—or all three. See our Expert Advice article, Insoles: How to Choose.
Break your boots in before your first trip. Too many sore-footed hikers overlook this important step. Read our article Breaking in Your Hiking Boot to learn how.