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How to (Secretly) Figure Out Your Girlfriend’s Ring Size

how to secretly determine ring size



  1. Go with the average ring size
  2. Try a larger size and resize it later
  3. Don't rush, be subtle, work while she sleeps, and use her other jewelry as a baseline (trace the ring and get that sized!)
  4. Ask for help from others (mom, friends, your friends, a jeweler)
  5. Playfully ask her
  6. Test it with a costume ring

Still have engagement ring questions? Visit our Engagement Ring FAQ and get all your questions finally answered!

If you’re thinking about proposing to your girlfriend, there might be a million questions running through your head. Some answers might come easily, such as where you want to pop the question, how you’ll do it and how to buy an engagement ring on a budget.

But as all the logistics start to come together, you might be wondering: how do I find out my girlfriend’s ring size?

Determining the ring size for your girlfriend can seem like a decision that could hold up the whole process. When she tells you yes between tears of joy, she’s going to want to put the ring of her dreams on her finger – and you’ll both want it to be a perfect fit.

If you’ve kept every detail about the proposal as a surprise, then don’t let the task of how to figure out your girlfriend's ring size stop you. Many men have come before you and pulled off this part of the process with ease. We’re here to help with our online ring sizing guide!

Start With the Averages

average ring sizes for women

The average ring size for most women is between a size 5 and size 7. We also know that the average sized woman in the U.S. is about 5-feet 4-inches tall. You can go off these averages to determine her ring size without her knowing. If she’s shorter or weighs a little more, you can go up a size or two. If she’s thinner and taller, maybe try a size down. You get the idea.

While this might work, it isn’t the cookie cutter way to find a ring size. Everyone is different and not every woman is going to fit in with the average. Some women also like a tighter-fitting ring, while others prefer a loose fit.

It’s a good idea to keep in mind that the dominant hand might be a little bigger. So if she’s right handed, her ring finger on the left hand—where she’ll wear her engagement ring—might be smaller in size than the one on the right.

If you’d rather not guess on her ring size, there are plenty of other ways to find out your girlfriend’s ring size at home.

Some Rings are Hard to Resize

If all else fails, try going with a larger ring size. The idea here is that it’s always easier to size down than it is up. Sizing up is trickier as the jeweler will need to add extra gold or other metals.

Ring guards also are great because they pop inside the band and allow your new fiancée to show off the ring without fear of it slipping off. She can still wear it until she decides to get it resized.

While the ring guard is a temporary solution, resizing will need to be done at some point if the ring doesn’t fit. Keep in mind that rings with side stones or pave bands can be tougher to resize, so you want to be pretty set with the correct size when you purchase rings with these details.

Keep it a Secret

secretly determine girlfriend's ring size

If you don’t want anyone to know about the proposal, then you’re going to have to do some of this work on your own. But fear not: There are plenty of options to find out someone’s ring size without them knowing.

  • Take your time

No one will start sending out wedding invitations until you’ve popped the question. In this situation, you are the master of time. Nothing will happen until you ask your girlfriend to marry you.

So plan ahead. If you bring it up subtly in conversation over time, she might not notice. If she’s on full proposal alert, tread lightly. Just make sure you’ve given yourself enough buffer time to do what you need to do.

  • Be subtle

If a jewelry commercial pops up and you take it as your cue to start asking her about what kind of jewelry she likes, she might get the hint. If you can, lead the conversation – or let her take charge with your guidance. If she comments on a jewelry commercial, saying she likes or dislikes something, take that as a cue to ask a follow up question – such as why? If a friend or family member gets a new piece of jewelry and starts showing it off, use it as a jumping point to ask subtle questions or as an opportunity to listen carefully to what your girlfriend says.

You’ll not only get a better idea of what style she likes, but you might get around to getting her to reveal the size.

  • Sneak in while she sleeps

If she falls asleep on the couch during Sunday football, this might be your opportunity to do the measuring yourself. Remember to measure the correct finger—she’ll be wearing this on her left hand, second finger next to the pinky!

Grab a small string of some kind and lightly wrap it around the base of her finger. When you pull it away, mark the length of the string with a piece of tape or marker. Take it the jeweler when you go to pick out the ring and you’ll be pretty close to the perfect size.

  • Check the jewelry box

Checking her jewelry box is one of the easiest ways to determine her ring size. Just be careful. A ring she wears on her thumb or middle finger will be very different in size than the one she wears on her ring finger.

It might be best to take in a few different rings from the jewelry box and have the jeweler get the average size. Or, take notice if she sometimes wears a specific ring on her ring finger, and use that one for measurement! (Trace out the ring on a piece of paper, and bring it to a jeweler for sizing!)

Just be sure to return the ring quickly before she notices!

  • Improvise your measurement tactic

If you’ve successfully found a ring in her jewelry box, but don’t want to risk taking it away for the day, you’re still in luck. You can do two things here.

The first option is to grab a bar of soap – the hotel mini bars are the perfect size – and push the ring down into the soap to get an imprint. Make sure you wipe away any soap residue, otherwise it’s a red flag and can potentially give you away! The second option is use wax, and to push the ring over a candle stick. When the ring stops, make a mark on the candle stick. Again, make sure there isn’t any waxy residue on the ring. Now you can take the soap or candle to the jeweler to help find your girlfriend’s ring size.

If neither of these options seem like they might work, trace the ring. Get a piece of paper and a pencil – be sure to use a pencil, as a pen could ink onto the band of the ring. Lay the ring on the paper and trace the inside circumference of the ring. The jeweler will be able to size the ring from your tracing. Tracing is a safe option, so you don’t have to worry about sneaking the ring out of the house or getting it dirty with soap or wax. 

Still no luck?

Try slipping her ring onto your finger. It will be too small, but that’s OK. Mark on your finger where the ring falls. Now head to the jeweler and let them measure the mark to determine the size of the ring you tried on.

Get Help From Others

get help sizing rings

Sometimes, it’s best to recruit family and friends to help with this endeavor. If you’d still like to determine her ring size without her knowing, make sure whoever helps you can keep a secret.

  • Ask her mom

If you’ve asked her dad for his blessing to propose, it’s likely that mom knows the big event is coming. She might know her daughter’s ring size thanks to a mother-daughter bonding conversation in which the topic came up. Mom also might be able to ask her more directly without it seeming like an out-of-place question.

  • Get her girlfriends

Other engaged or married girlfriends can be especially helpful. If they talk about their own wedding plans, it’s easy for them to chime in and ask your girlfriend about her own dream wedding day. If they’re inventive or willing, they can arrange for an opportunity for your girlfriend try on their rings, and report any information back to you.

You might even be able to encourage them to make a day of it. Have the women go shopping and conveniently end up at a jewelry store, where they can try different rings, and her girlfriends can determine what size ring your girlfriend wears. If you let the jeweler know in advance they’re coming, someone can keep tabs of what rings she tries on and what her proper ring size might be.

Just don’t let your girlfriend know there’s a master plan. Have one of her friends make up a story or simply say they want to have a fun girl’s day and try on jewelry.

  • Ask your buddies

Do you have a buddy who is also planning to propose? Have him ask your girlfriend for help. It’s likely she’d be more than happy to tag along to the jewelry store to model a few rings for him or give her opinion on style. While she thinks she’s doing your friend a big favor, he’s actually the one helping you out.

If you think you could get away with it, you might even tell your girlfriend you want to pick out a ring for someone else, such as your mother or grandmother, and have her go along to help out. Slip something on her finger while you’re there to see what might fit.

  • Make it a game

By cleverly disguising a question about finger size into a game, you can get your girlfriend to spill the beans on her ring size.

Tell her you heard that dividing a shoe size by two and adding three equals the size of your ring finger. While the science doesn’t back up the calculation, you’ll be able to figure out her ring size.

If you’re careful and frame this into a true/false question during trivia one night with a group of friends, she might not even guess that you’re trying to buy her an engagement ring. If it’s coming from someone else, she’s less likely to be suspicious!

  • Get the jeweler to help

Does she have a birthday coming up or big accomplishment you’d like to celebrate?

Tell your girlfriend you’d like to take her to the jewelry store to pick out a special gift, such as a bracelet, necklace or earrings. While you’re browsing the many items under the glass, have her try on some rings for the fun of it. If you don’t want to make the suggestion in fear of giving away the proposal, speak to the jeweler in advance and see if they can help you out.

While you look at things in the case, the jeweler can offer to pull out some rings. Your girlfriend might not be able to turn down the chance to try something sparkly on her finger!

The bonus here is that you get to give her a special gift and find out her exact ring size at the same time.

  • Be a goof

If you’re at a festival or other art-type show and you see a display of rings, maybe start trying some on. The gaudier, the better. Make a joke out of it and show her that you’re fooling around. Try to get her to join in and you might get her to slip one on her ring finger.

When she does, you’ll be able to know if it fits!

  • Pull a dummy

If you think you know her ring size but want to double check, buy a costume jewelry ring. Tell her you won it in a game, found it lying on the sidewalk or that a friend bought it for his lady but she didn’t care for the style. If your girlfriend likes the ring enough, she’s likely to slip it on, even just to see how it looks.

Now you’ve got the ring on her finger and you’ll know if the size is right. If it’s too snug or too loose, you know to change it by half a size or so.

Buy The Ring of Her Dreams

You’ve done all your homework. You know where you’ll propose, what you’ll say and how you’ll do it. Now it’s time for the ring. Don't forget to check out our guide on finding the perfect diamond.

Stop by Thom Duma Fine Jewelers and let our specialists help you find the engagement ring of her dreams!