Yes, Old Navy clothes do run big, almost without exception, so at least that's something you can count on. You can find a sizing chart on Old Navy's website. Old Navy actually makes their size charts specific to the item of clothing you want to buy, so first find exactly what it is that you want, and then when you click on that individual item and it asks you to select a size, you will notice that right above the "add to bag" icon is an icon that says "size chart." This is great since your size may be different in skirts as opposed to pants.