Nipple piercing size?

Hi there! This might seem like a bit of a silly question but I really have no idea 😬

I got my nipple pierced about 16 months ago and they are completely healed and doing well, so I’ve been wanting to try getting some new jewellery to try in them.

Only problem is I have no idea what size the piercings are! Does anyone know how I can easily and accurately measure this?

Jewellery I’ve seen at some shops all looks like it would be way too long, and I also would want to make sure the bar is the right thickness..

Sorry if this is a really obvious question - there’s a lot I don’t know! Thanks in advance for the ideas ☺️