Jasper Zionic

KEEN’s general rule: go up a half size from your standard shoe size, then work from there. Your fit history in other shoes is a good starting point.

KEEN shoes have a roomier toe box than many brands, but standard widths: women’s styles are a B width and men’s are a D width. Hiking and trail styles fit snugger; casual and city styles fit more generously.

Fit to your larger foot. Left and right feet often differ, so measure both.

If you’re between sizes, choose the larger size (KEEN’s advice). You can fine-tune the fit with socks, insoles or lacing.

How much room? About a thumb’s width at the toe — roughly ½ inch (1 to 1.5 cm) between the longest toe and the end of the shoe. Toes should wiggle freely without the foot sliding forward.

Thumb test: with your child standing, press the tip of your thumb down at the front of the shoe. You should be able to press down without hitting a toe.

Between sizes or one foot bigger than the other? Choose the bigger size. Kids’ feet can grow quickly, so re-measure about every two months.

Time for a bigger size if toes are pressed against the front, the shoe leaves deep marks or blisters, or your child says their feet hurt. Too big if their heel lifts out when walking, or they trip or drag their feet.

Waterproof styles (KEEN.DRY or eVent): less room in the toe box, so sizing up is sometimes needed.

Original Fit (Newport, Targhee II, Austin, Presidio): KEEN’s roomier fit. Contoured Fit (Terradora, Venture): closer to a traditional regular width.

Bungee-lace styles (like the Newport H2) adjust to different foot widths, including narrower feet.

1. Stand on a sheet of paper with your heel against a wall, wearing the socks you’ll wear with the shoes.
2. Mark the tip of your longest toe.
3. Measure from the wall to the mark in centimeters.
4. Measure both feet and use the longer one.
5. Measure later in the day, when feet are at their largest.