.5 size difference for NIKE SBs

I normally wear a size 12 for nike sbs but I am debating on whether to bid on some nike sbs that are size 12.5. I was wondering how much bigger will the shoesbe compared to a size 12 and will I fit in them comfortably? Any opinions/help is appreciated. Thanks.

for lows you'll probably be fine, if they're highs they'll crease to kingdom come.

for me

11.5 regular dunks and SB His
12 SB lows