What jean size am I in online stores?

I really want to buy jeans online, but I can't help but be a bit cautious if I'm ordering the right size. I know I'm a perfect 3 in L.E.I. jeans and I have a 34-36 inseam depending if I'm wearing heels or not. If I am a 3 in LEI what will be my size in all the main online stores like Delias, Gap, UrbanOutfitters,Revolve Clothing, Express, Nordstrom..anything. If anyone knows their LEI size and know your sizes in these stores can you please tell me since it's equivalent? Thanks!