Waist sizes

Ashley

Can someone please explain to me how to figure out what size waist for jeans?! I really like buying on Mercari and Poshmark, but im in between a size 2 and 3 in most brands, and figuring out the waist in what I think is inches is so confusing! I have 1 pair of Hollister jeans that say W-26, which is a 3, but when I type 26 most of the jeans come up in size 5...🤦‍♀️ help! I'm a 26yr old mom of 2 with clothes from high-school