How to Measure Ring Size – The Ultimate Sizing Guide

engagement ring measured and sized to fit perfectly on the ring finger

So you’re planning on popping the question and you’re picking out the perfect engagement ring to #putaringonit. Chances are you’ve hit the roadblock of how to measure ring size. We here at GWS know that the process of figuring out ring size can be a liiiiiiitle confusing, so we invited the experts over at Diamonds Factory to break it down for you so you can pick out and size that engagement ring with confidence.

The Truth About Measuring Ring Size

Ben Stinson, Head of Commerce at Diamonds Factory, tells us, “A lot of people get ring size wrong the first time. In fact, around 30% of the engagement rings we sell are sent back for re-sizing. While getting the size wrong isn’t the worst issue in the world, having the perfect fit can really add to the magic of the moment!”

We’re here to make sure measuring ring size is an easy process. A proposal is one of the most exciting moments in anyone’s life. It’s a promise to spend every day with your best friend, to build a life together, experience adventures together and, of course, it’s a chance to show off a beautiful sparkling ring! One worry that shouldn’t cloud the special day’s enjoyment is whether or not the ring will fit.

That’s why the experts at Diamonds Factory have created a handy guide on how to measure ring size to take off some of the pressure. Once you’ve settled on the ring’s shape and size, you’ll need to measure (or try to sneakily and secretly work out) your partner’s ring size.

When measuring ring size, ideally the ring should be tight enough that it doesn’t fall off but loose enough to take it off if need be. By following the steps below, you should be able to find a ring size that fits your partner perfectly!

how to measure ring size sizer thread

Finger Circumference to Ring Size

Let’s talk about translating finger circumference to ring size. In order to accurately measure ring size using this method, here’s what you need to do:

  1. To measure the circumference of a finger, wrap a thin piece of string (or even dental floss) around the base of the ring finger and mark it with a pen.
  2. You can then lay the marked string out against a ruler, measuring in millimeters, which will enable you to measure the ring finger circumference.
  3. If the knuckle is much larger than the base of the finger, measure the circumference of the knuckle too, then pick a measurement that is in between. You must do this as carefully as possible to get an accurate reading.
  4. Measure ring size up to 3 times for greater ring size accuracy.
  5. Use a ring size chart to find the correct size.

Ring measurement pro tip: be wary not to tug on the string or floss too hard as this can stretch it and make the measurement less accurate.

engagement ring measured and sized to fit perfectly on the ring finger

Something Borrowed – How to Secretly Measure Ring Size

If you’re planning a surprise proposal and think that measuring your partner’s finger with a string might be a little too obvious, consider borrowing one of your partner’s existing, well-fitted rings to measure the diameter.

When measuring ring size, the diameter is the measurement across the inner width of the ring. To measure this, grab a tape measure or a ruler and measure the widest points of the inside of the ring – from edge to edge.

If possible, try to use a circular ring for the most accurate reading of their ring size. If your partner doesn’t have a circular ring to measure and you’re instead trying to measure a ring of a different shape, measure the shortest distance across.

Once you have the ring diameter, match this with the closest measurements on the ring size chart to learn the correct size. Alternatively,  you could take the ring they already own to a jeweler who will be happy to measure and size it for you.

Of course, do bear in mind that most people don’t wear a ring on their wedding finger before they are engaged and most fingers are usually different sizes. But, while it may not be entirely accurate, this method of measuring ring size should be pretty close.

how to measure ring size sizer thread

Something Blue – How Tight Should a Ring Be?

When measuring for the correct ring size, something else to remember is that fingers expand and contract depending on the temperature. Too hot and they’ll often swell up, too cold and they’ll be slightly smaller than usual. They can also expand throughout the day depending on factors like activity and water consumption, and all of this can impact how you end up measuring your partner’s ring size.

So how tight should a ring be, and how can you avoid a ring that doesn’t fit quite right? If you decide to measure your partner’s finger yourself, or even if you go into a jeweler to have them professionally measured, try to do this on a mild day and toward the end of the day.

Also, keep in mind that fingers on the dominant hand are usually larger. So, if your partner is left-handed for instance, their ring size could be a little bigger.

engagement ring sitting inside a blooming pink flower

photo: Anna Delores Photography as seen in this colorful brunch wedding

How to Guess Ring Size

While guessing your partner’s ring size may sound risky, it’s actually not unusual. So how can you make an educated guess when measuring ring size? Generally speaking, our fingers are proportionate to the rest of our bodies, which gives us a good place to start when figuring out ring size.

If your partner is petite, they’ll likely have a smaller ring size. Likewise, if they are a bigger build, you could assume that their ring size may be on the larger size.

The average engagement ring size for women in the UK is L-O (an inside circumference of 51.2mm to 52.5mm). The average engagement ring size for men is UK S-T ((an inside circumference of 60.2mm to 61.4mm).

If you can’t get away with borrowing their ring for a day, another way to make an educated guess while measuring ring size is to playfully slide a ring they are already wearing onto your finger and quickly mark it with a fine pen where on your finger it gets stuck.

This is dependent on whether your partner’s finger is smaller than yours. You can then measure your finger at this point or ask a jeweler to measure it for you (clever, right?!).

 brilliant shining diamond engagement ring on a silk ribbon

photo: Lerina Winter as seen in this jungalow-style wedding

Ring Resizing – What if I Order the Wrong Ring Size?

Ring resizing is totally normal! Ben at Diamonds Factory tells us it’s not the end of the world! “First of all, don’t panic. Mistakes happen when buying an engagement ring as a surprise. You can never be certain your measurements or guesses are completely accurate. Plenty of people don’t get the size right the first time. But, usually, you and your partner are in such a happy bubble at the time that it doesn’t matter. Especially as you can always take your partner’s ring to be resized after the romantic proposal!”

Diamonds Factory offers a 60-day free ring resizing service for up to 2 sizes up or down. If you are concerned about resizing or exchange policy when buying a ring, simply ask the jeweler who you are purchasing from. Most jewelers will be very transparent regarding their policies which can help you relax when making the purchase!”

Feel like you’ve nailed the process of how to measure ring size? Check out our A-Z guide on how to buy an engagement ring. Already have the ring? Make sure you get it insured!