Adidas sizing

[Trallala]

Hi, quick question: if I usually take an 8.5 in Converse, will I be an 8.5 in Adidas? I know sizes can vary between brands but I've never bought Adidas shoes before and I'll be buying online. For reference I'm quite a narrow fit.
Many thanks

I’m usually 5.5 in footwear and wear and Adidas 6. Same for my DH, he’s a pretty solid 8 but wears 8.5 Adidas. His feet are wider but mine aren’t.

@boombasticfantastic that's really helpful, thank you!