10 August 2026
Should winter boots be a size bigger?
Yes, roughly one size, and there is nothing mystical about it: the extra room is for a wool sock and five months of growing. Here is the arithmetic.
A winter boot has three jobs a sneaker does not: it goes on over a wool sock, it stays on from October to March, and it must not pinch a foot that grows about half a size in that time. Stack those up and you land on 10 to 15 mm of space beyond the measured foot, which in practice is one EU size.
The boot makers say the same thing in their own dialects. Kuoma prints the inner length of every boot and asks for 15 mm of free space in front of the longest toe. Viking bakes the growing room into its chart and recommends adding 10 to 15 mm to the measured foot. Two brands, one number.
The method, thirty seconds
Stand the child on a piece of paper against a wall in the evening, feet swell during the day. Mark the longest toe, measure from the wall, add 15 mm, and buy the size that clears that number. If the foot sits at the top of a size's range, take the next one; thick socks eat margins fast.
One honest caveat: more than about 20 mm of slop and the boot starts working against the child, heels lift and toes claw. Bigger is not better without limit. One size up, measured, is the whole trick.