February 07, 2020

How to Figure Out Your Girlfriend's Ring Size

By Elizabeth Christenbury


Some of these ring sizing methods will make for a funny story after the proposal!



Ringcrush is all about alternative engagement rings. However, before you even begin shopping for rings, you need to get your partner's figner size. Follow this guide for easy ways to figure out her ring size without her knowing. 


The Professional

When she's looking the other way, steal one of her rings, and slide it onto a professional goldsmith's ring mandrel. Simply note at what numbered line on the ring mandrel the ring falls, and voila! You now have her ring size. This ring sizing stick has marks which can indicate sizes as small as quarter sizes.This is the best way to get an extremely accurate ring size, as long as the ring you swipe fits her ring finger!


Note: If you have raided her jewelry box, and found multiple rings that she wears on her ring finger, measure as many as  you can and take the average of all of the sizes. 


You know how bars of soap get a little squishy when left wet for too long? Simply press the ring into a soft bar of soap, which will make an impression that is the exact size of the ring. Wash the ring to hide the evidence, and put the soap bar in a zip-lock baggie to ensure it doesn’t shrink by drying out. As a side note, make sure you don’t sit on it. (Yes, this has happened before!)


Acquire Soft Soap - Or soak soap in water for 20 minutes.

Press ring into soap to leave an impression.


Inspect impression, if it looks even, gently pat dry with a paper towel, and then place soap in a tupperware or a ziplock to protect it. Take the soap to your jeweler and they will be able to give you the ring size. Alternatively you can also measure the impression or ring yourself, by finding the diameter of the inside of the ring (with a ruler, measure the widest spot in the negative space of the ring). Use this handy Wikipedia Chart to determine the formal ring size. 


You can also use candle wax, play-doh, clay, or another soft medium to press the ring into. 



Trace the inside and the outside of the ring shank using a pencil and paper. Try several times and your jeweler can take the “average” of all of the diameters.  If your pencil is slightly off this could end up causing some problems, and if your girlfriend finds the sketch it will be difficult to explain.



OK – This is as dangerous as it sounds. Steal one of her rings, and take it to a jeweler to determine the size. They will probably use a ring mandrel, so if you would like to measure it yourself at home, you can acquire one inexpensively here. Depending on how emotionally attached she is to the ring, you may end up in hot water if she notices it missing.


Ask one of her friends

Girls try on and borrow each other’s clothes and jewelry all the time. If her friend doesn’t already know her ring size, have her try a few techniques that will be MUCH more secretive than if you do them yourself!

  • Have your girlfriend’s friend take her engagement ring shopping for fun! Kill two birds with one stone, discover her size and her style. This way she is professionally sized, eliminating the possibility of mistakes.
  • Ask your girlfriend’s friend to try on your girlfriend’s favorite ring. She can pretend she wants to see what it looks like on her hand. During this conversation she needs to make sure that your girlfriend actually wears this ring on her ring finger, and that it fits. Have her smoothly say, “It’s too big/small on me, does it fit you?”
  • Hole in one: Have the friend steer the conversation to ring sizes. If you are lucky, your girlfriend knows her magic number, and the friend can directly ask for the ring size without your girlfriend batting an eyelash.
  • If she doesn’t know her own ring size, don’t worry! Have the friend put the ring on a finger that fits her, or to a knuckle that fits. Have her remember this spot, and use of of these $5 ring sizers to determine the magic number. 

Caution – Ask the friend that can keep her mouth shut! No point in secrecy if her best friend is guaranteed to blab.


Knuckle Trick

On that last point, this is a technique you can do yourself if there is no friend “handy” – ha! Simply slide her ring onto one of your fingers to where it fits comfortably but is not too loose. It is OK if this is above a knuckle. Remember the spot and have yourself sized at a jeweler. The professionals behind the counter should be able to get the size pretty close. Again, if you would like to avoid a trip to the jewelry shop, you can buy an inexpensive tool to figure out the size. Simply use these sizing rings by sliding them one-by-one onto your fingers, until you find one that matches where her ring landed above your knuckle. 


Rings can be resized!

So don't worry, most rings can be resized. Err on the side of a larger ring, if you are uncertain. For one, she will at least be able to wear the ring temporarily if it is too big. Second, removing gold for a smaller ring is less expensive than adding gold to make a larger ring. Alternatively, there is an option to “Stretch” a small ring using special equipment, but this can often compromise the structural integrity of the ring. There are often many factors that can make resizing an expensive process, so it is best to get the size right on the first go.


No Surprises

We are assuming you wouldn't be here unless you are planning on a surprise proposal. However, if your partner isn't really all that into surprises, you may not wish to eliminate the idea of including her in on the ring shopping process. According to DeBeers, only 19% of engagement rings are purchased as a surprise. Stay tuned for an article explaining how to propose to your girlfriend without a ring.




All blog posts written by Elizabeth Bailey Christenbury. She welcomes you to connect with her through Twitter, Facebook, or Instagram by clicking the icons below.