How do I get the right size of wedding ring as a surprise for my fiancee?
You can get in the ballpark (like chrisamiller mentions) if you know how small or big her wrists are. If she’s ever had trouble with bracelets fitting properly (i.e. they’re either too big or too small) then you can choose a ring on either end of the range and have better luck in resizing. If she’s “normal sized” then just pick something in the middle of the range, like a size 7.
This is easy: ask one of her girl friends. Most girls talk about that stuff. They can also usually be roped in to keeping it a surprise if you let them know you’re trying to surprise your fiancee. I have two female friends who have specifically designated each other as the person to go to for ring sizes. If your fiancee doesn’t have any friends… using your fingers as a template isn’t that bad an idea.
If you feel comfortable cluing a friend/family member in, get them to find out for you. I bought a (non engagement) ring for a former girlfriend and I had one of her friends get the info by saying something like “you know, my fingers seem like they’re getting fatter. I can’t seem to wear some of my old rings anymore.” The conversation continued and she got my girlfriend to mention her ring size. This does assume that she actually knows her own ring size. But in my case, it worked like a charm and she never suspected a thing.
Most people are terrible at guestimating ring size based on built/eyeballing it/whatever. (I’m pretty good at it, but then again, I’ve sold jewelry.) Get her friends or sister to find out. Easiest way for them to do this is invent a reason to shop at a jewelry store, get their own fingers sized, nudge clerk into sizing your girl’s fingers as well. Other scenario is for someone to nudge her into trying on their own rings to see how they fit. If you need to base it on the size of another figure, it may be useful for you to know that a general ballpark is that a woman’s pinky is usually about two sizes smaller than her ring finger, which is about two sizes smaller than the middle and index finger (which are much closer in size.) If you want to try measuring in her sleep, use a piece of string for a more accurate reading than a piece of paper.
I’ve heard ring size and shoe size can be related, but that doesn’t always pan out: I used to work in a jewelry store, and this is a complete urban legend. Totally false. Your best bet is probably to take a friend who has similarly-sized hands, and not sweat it too much. Re-sizing most engagement rings is an easy, quick process that your jeweler will be happy to do for you. If you find yourself having to guess, try to guess on the high side, as that way you can at least slide it on her finger, even if it won’t stay on, and it’s easier and cheaper to size a ring down (you’re cutting gold out of it) than size it up (you’re adding gold to it).
