Before I left for my trip to the States in December, I asked on here about diaper sizing in Europe vs. the US. I finally was able to blow up pictures of the Pampers wrappers from amazon to read the weight recommendations, which were a lot different from the European ones (and there are lbs and kilos on both, so it's not like I converted incorrectly). Based on that, it seemed that even though DD was in 3s over here, she would need 2s in the US. I even found a diaper sizer on the Pamper's US website where you put in LO's height, weight, and age and they tell you the recommended diaper size and it said 2 for her.
So we got to the US, I tried on a 2, and it was definitely the same size as 2s in Europe, and thus too small for DD. Luckily I had told my parents to get a small package of 3s just in case, so we ended up donating the 2s to one of my mom's coworkers with a newborn.
Anyway, I just wanted to let you know that if you use Pampers, you can just stay with the number you're using in Europe, at least if you're using a 2 or 3.
Re: @ f/u on diaper sizing (bit of a PSA)
I also thought this - I had some 3s from here still and the US 3s were noticeably lighter weight. I don't know why that is, but I also had the feeling that they absorbed less.
Gah! There are so many tiny details that I can drive myself insane about, while prepping for our move.