My daughter is 11 and very average for height and weight. She wears a size 10/11 in H&M jeans, size 12 in Target Art Class Jeans, and in wild fable she wears an xxs. . Me: I am 5’2” and 115/120 lbs. Wide leg jeans: size up one (in a 2 here) Black jeans: Fit TTS (0 regular) Black Trousers: size 26 (size up one) . All F21 items: size up one. I find most stuff runs small.