Scarpa boots sizing help

[WhateverEh]

i can choose between size 5.5/39 and 6.5/40. I usually take a size 6 which says 39

I normally take a 38 in my favourite Italian trainers but I went up to a 40 on the advice of the Scarpa fitter, to allow for thicker hiking socks.

Not scarpa, but I normally wear 39, bought hiking boots 39.5 and they are too tight. I have been suffering for months and will wear them with some pain but definitely buying 40 next time. Worth going just a notch higher.

I usually wear everyday socks with my boots but it still sounds like 40 might be the right size for me