I'm trying to sneak a finger size to surprise someone

Right, time to get your Bond on. You can:

MEASURE A RING THEY ALREADY HAVE

First, though, you need that ring. This may take some sneaking around. ALSO! Make sure they wear it on the same finger the new ring will be worn on (for engagement and wedding rings, this is your left-hand ring finger).

Once you have the ring, it's time to measure it. See How To Measure Your Ring.

GET HELP FROM A FRIEND

Your partner’s friends may be able to help get a ring of theirs to measure or already know their ring size. They might even “try on rings for fun” together the next time they’re out shopping.

JUST ORDER AN AVERAGE SIZE

We offer free Resizing and Returns, so if all else fails, just pick a size and hope for the best! The average women’s size is US 6 and men’s is US 9. 

Please know that titanium cannot be resized, so never guess when it comes to titanium. And for custom designs, we like to have the size sorted from the start.