Sock sizing for kids?

[ahisma]

How does sock sizing work for kids? I've been buying socks from CP and ON that are sized by age, but want to order some smartwool socks for winter walks to school.

I can't believe I can't figure this out!

[NCGrandma]

I've learned about Smartwool sizing because I made the mistake of starting a 'Smartwool for Christmas' tradition ;)

Most of the socks are sized by shoe size, not by age, at least after the baby/toddler sizes. For kids socks, XS is shoe sizes 6-8.5, S is 9-11.5, M is 12-2.5, L is 3-6 (from the Smartwool website -- which is sort of hard to find info on...). In general, I think they are more or less true to size but on the generous side.

For the youngest Smartwool wearers, I think they are sized by age (e.g., 12M), but the baby Smartwool socks look HUGE to me.