2
I wear one but at h and m I wear a two in pants and a four in skinny jeans! We might carry weight differently though so you should look for a store nearby to try them on! Good luck :)
Then go next size up - size 2...size 2 shouldnt be too different from size 1 But for my H&M in the mall the sizes for pants like 25, 26, 27, 28...not 1,2,4,6 (those are for the tops and stuff) but maybe online its different Anyway Id go with size 2, cant be too off, also I seem to remember their sizes run kinda small