How to Determine Your Ring Size

Curious about how to measure a ring size? Most people have no idea what their beloved’s ring size is until the time comes to purchase one of the most important pieces of fine jewelry one will buy in their lifetime. It is not common knowledge to know your ring size off the top of your head, which is why your loved one might not even know their own either. Ring size is one of the first key steps in what to know when buying an engagement ring and with some simple tips, you will become an expert at finding your correct ring size. If going to a jeweler to determine you or your loved one’s ring size seems rigorous, try at-home methods that are just as accurate.

The journey to purchase engagement rings or
wedding bands often starts with the question “How are ring sizes measured?” Once you understand a few key pieces of information, you’ll know how to properly find the right ring size for you or your loved one and find a ring that fits like a glove. Most of these approaches can be done in secret, but for the most accurate results, it is best to perform them on your bride-to-be. No matter if you are making the decision alone or together, the size can still come out perfectly. Here are a few tips on how to know your ring size to get you started.

A Diamond Nexus engagement ring being sized on a ring mandrel.

Understanding Ring Size

Before purchasing an engagement ring or any kind of right hand ring and simulated diamond jewelry, whether for yourself or someone else, you need to determine the correct ring size. How to know the ring size for engagement ring purposes is essential. The size of a finger is typically recorded in millimeters to be as precise as possible. Because of this, ring sizes are usually shown with a matching millimeter finger size. Matching these measurements to the closest degree is the best way to determine your ring size. Before beginning your search, you need to know how to find ring size – not only so the ring fits, but also to ensure it will not fall off during everyday wear. Although having a jeweler measure the intended finger may relieve any doubts you have, it is always best to have an understanding for yourself too. Plus, if you are planning a surprise proposal, going to the jeweler may not be an option.

Men and women tend to vary greatly in standard ring sizes. The average ring size of a woman is between 6 and 8, while the average size of a man’s is between 9 and 11. However, that does not mean you will necessarily fall into these parameters. Many people live outside the average ring size as referenced in a ring size chart for women and men. But no fear, finding beautiful engagement rings for small hands or large hands that fit your style and finger isn’t as daunting as you may think. According to the U.S. and Canadian measurement scale, ring size can range from 3 to 13.5 for adults, with a size 3 measuring at 14mm and a size 13.5 measuring at 22.6mm. For better reference, ring size increases by a 0.4 mm increment for every half size up. If you do not want the ring to fall off, or worse, not slide on her finger during the proposal, you should obtain a more accurate measurement.

A Ring Size Guide featuring the different millimeter widths of popular sizes.

Why it is Important to Know Your Ring Size

If you are planning a proposal and have begun imagining all of the things that could go wrong, you are not alone. It takes a tremendous amount of planning and can be extremely nerve-wracking, especially if you are planning to do it in front of a crowd. However, there is at least one thing you can control, and that is making sure the ring fits when you get down on one knee.

Proposing can often be an embarrassing moment due to the immense amount of pressure. You have to ensure you put the ring on the right finger, remember all of the important things you want to say, and ensure you get all the right photographs. You would not want everything to be ruined with a ring that does not fit on her finger, or is so loose that it will not stay on. That is why it is extremely important to have the correct ring size for the proposal. It does not have to be 100% perfect, as most rings can be resized later, but purchasing the right ring size is a must when you finally pop the question.

How to Determine Your Ring Size

If you are not planning on visiting a jeweler before purchasing an engagement and wedding ring, you can find your ring size yourself or with the help of another person. There are a few different at-home methods to measure ring size that are just as accurate as using a ring sizer from a traditional jeweler. The difference with these methods is that you will be able to do so in the comfort of your own home, as opposed to visiting a traditional or simulated diamond shop. This will also prevent her from finding out you visited a jeweler and help you keep the surprise a secret until the big event. There are many ways that you can determine your ring size at home including:

  • Tying a string around your finger and make marks on the string to be able to measure it in millimeters.
  • Using a current ring that your partner wears and taking it to the jeweler to have them size it.
  • Using a ring sizing kit that you can purchase from a jeweler or online store
  • Measuring a friend’s finger that has similar sized fingers.

All of these at-home measuring methods should be performed multiple times and to the utmost precision for the most accurate results. Mistakes can be easy to make when using these measuring tips, which can result in the wrong ring size. It is best to have someone with you for a second opinion, whether that be your loved one or a friend. If you don’t have a ring sizer at home, do not worry. This ring size guide offers popular approaches to ensure you find the perfect ring size.

Shop Engagement Rings

  • Tie String Around Your Finger to Determine Ring Size

One of the most common ways to measure your partner’s ring size at home is to use household items, such as a thin strip of floss, thread, or string. Start by tying it around the finger you want to measure. Make sure it’s not too tight, as you will need the ring to slip off with ease. Make marks on the material where the two ends meet. Once it is off your finger, place it next to a tape measure or ruler, and mark down the ring measurement in millimeters. A caveat to this method is that both string and floss can stretch, so be careful not to force it too tightly around the circumference of your finger. If you do end up stretching it, you may be left with a ring size slightly smaller than the actual size needed.

A ribbon tied around a finger and then compared next to a ruler to determine ring size.

You will want to complete this task a few times to ensure you get the same measurement every time. Be aware that you and your partner’s finger size can be affected by temperature. A cold environment can actually cause your finger to shrink, which is why it is best to perform this task at room temperature. In addition, fingers can be slightly larger at the end of the day depending on what you eat and how much salt you consume. It is best practice to measure the circumference of a finger with a tape measure in the morning or early afternoon to get an accurate measurement.

  • Use a Current Ring to Help You Determine Your Size

If you are not able to complete the first option – whether due to lack of household items or because you are keeping it a secret and can’t get a measurement of the wearer’s finger – there are other ways you can complete the task of measuring ring size. While finding a way to score your girlfriend’s ring size without their knowledge may be more difficult, it’s not impossible. A great way to find her ring size in a discreet way is to use one of her current rings. Before measuring, make sure it is a right-hand ring that she does not wear on her thumb, middle or index finger as these will be different sizes than her left ring finger.

Multiple Diamond Nexus engagement rings in white gold.

If you take it to a jeweler to get sized, they may use a ring mandrel to measure it, which is a tapered metal rod. This tool can measure both full and half sizes to get an accurate ring size. If you do not want to take it to a jeweler, you can also measure it yourself at home. By taking a ruler, measure the diameter of the inside of the ring. Once you have taken the diameter of the ring in millimeters, you can use this measurement to determine the ring size. Some online jewelers provide a size guide that is printable. These guides usually include true-to-size ring figures to help you determine a ring’s size. Once you print it, you can compare the size of her current ring to the ones on the guide. This may not be as accurate as using a mandrel, but it will be a good start. Once you receive the engagement ring, you can then determine if it is the proper size. If it is not, most jewelers will provide a free resizing with purchase. Eternity bands are often excluded from resizing as it is much harder to change the size of a ring with stones around the entire shank. If you are looking to find an accurate size for an eternity band, it is safest to have a jeweler determine that rather than use an at-home measurement.


A ring sizing measuring tape wrapped around a finger to determine size.

Another option you have is to buy a ring sizing kit online. Since there are different kinds of kits, some will contain sample rings while others will contain a small measuring tape that easily wraps around your finger. Both will include a wide range of ring sizes, usually from 1 to 13, so you can use it for measuring both men and women. All you have to do is have your beloved try each size on until you find the perfect fit. To ensure you ring is the right size, make sure it is not too tight. It should slide over the knuckle with just a touch of resistance. This will keep it from falling off, but ensure it will not be impossible to take off when needed. If you have larger knuckles, it is recommended to size up by a half size to ensure you can slide the ring into place on the finger. You can usually find these at a fairly inexpensive price, but before you buy one, ask your friends and family if they own a tool like this. That way you can determine your ring size without taking funds away from your overall ring budget.


Although this method may be the least accurate way of measuring ring size, it will work if you do not have another option and are serious about keeping it a secret. If one of your bride-to-be’s friends has a similar hand size, you can use one of the above options to find her ring size. You will probably need to get the ring resized to be exact after the proposal, but this way you will not have to worry about ruining the surprise with hints about ring size.

You can also ask one of her friends to help you find her ring size so she does not become suspicious of you. Her friend could give her a right-hand ring to test her size, or sneak one of her current rings out of her jewelry collection. This way, your secret will be safe until the big moment.


  • It is better to buy a size up rather than a size too small. This is because it is easier to take metal out of a shank than it is to add it in. While jewelers usually include a complimentary resizing for rings that need to be sized down, you might have to pay more for a ring that needs to be sized up as it will need metal added.
  • When trying to understand how to determine ring size, make sure to think about the different parts of a ring. Consider the size of the shank. Wider shanks tend to fit more snug than thin shanks. It’s best to size up a half size if your shank is on the thicker side.
  • Remember that time of day and temperature can affect the size of a finger. If you decide to use the string or floss method, it is important to do it preferably in the early to mid-afternoon in room temperature. Hot temperatures can also affect finger size and may create sweat which interferes with accuracy.
  • Keep in mind that the ring fingers on your left and right hands are not identical and may differ in size. Because the fingers of your dominant hand tend to be slightly bigger than those of the non-dominant hand, be sure to measure the right-hand ring finger for the most accurate size as opposed to the left-hand ring finger.

An Overview of Ring Size

Now that you are equipped with the right tools and tips on how to figure out ring size, you will be able to accomplish the perfect proposal with a ring that fits just right. Determining her ring size without her finding out will be a thoughtful gesture, but measuring her size as a couple will be just as romantic and may even be more accurate.

Now that you can answer the question, “How is ring size measured?” you are sure to impress your bride-to-be, find the most perfect ring – whether that’s classic engagement ring styles or something more unique – and nail the proposal. Do not forget the important tips to help you find ring size and ensure nothing interferes with an accurate measurement. Use the resources you have, like friends and family who can help you as well. They may even be able to help you pick the perfect ring if they know the design details she is looking for in an engagement ring. Once you have chosen the ring and figured out her ring size, all you have to do is plan the perfect proposal. But with a ring that slides on her finger perfectly, you are sure to nail the rest.

How did you find her ring size? Tell us in the comments!

*Diamond Nexus strives to provide valuable information, while being clear and honest about our products. The Nexus Diamond™ alternative is a patented lab created diamond simulant that, among all simulants, most closely imitates the look, weight and wear of a diamond, with two exceptions – it is absolutely perfect in every way, and it costs significantly less. Price points and environmental facts expressed in this blog were taken from popular online retailers and may vary. Learn more about the environmental impact of mining by visiting our blog.

As Featured In

Contact Us

Two affordable Diamond Nexus engagement rings

Win a $2,500
Shopping Spree!

Enter our monthly contest for a chance to win a Diamond Nexus shopping spree.

Enter to Win

A $2,500 Diamond Nexus Shopping spree.

Two affordable Diamond Nexus engagement rings

Win a $2,500
Shopping Spree!

Enter our monthly contest for a chance to win a Diamond Nexus shopping spree.

Enter to Win

A $2,500 Diamond Nexus Shopping spree.