Infant/Toddler Crest Vibe Jr

Leather boat shoes stretch over time, so Sperry suggests considering a half size down from your regular size. Shoes made of synthetic materials won’t stretch — get your normal size.

Break-in only affects the width of a boat shoe, not the length.

Try boat shoes on toward the end of the day, when feet are slightly larger.

If your measurement is between sizes, or one foot is larger than the other, Sperry says to move up to the larger size. Half sizes aren’t available in every style.

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.

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.

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.

1. Stand on a sheet of paper, with your weight on that foot.
2. Mark the back of your heel and the tip of your longest toe.
3. Measure between the marks in inches or centimeters.
4. Measure both feet and use the longer one.
5. Measure later in the day, when feet are at their largest, wearing the socks you’ll wear with the shoes.