Your Guide to Determining Your Ring Size

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Your Guide to Determining Your Ring Size

When shopping for rings, buyers often concentrate on choosing the perfect design. However, it is very important that a shopper selects a ring that is the correct size. Unlike clothing, rings are worn day in and day out, for weeks or months at a time, and when it comes to engagement rings and weddings rings, they can be worn for for a lifetime. A ring that is too big can fall off and become lost. A ring that is too snug can affect the wearer's circulation. Although some rings can be resized, most can't, either because of the metal in the band or the type of setting. Therefore, if the buyer gets the size wrong, the ring could turn out to be a costly mistake that cannot be remedied.

Many people find the question of ring sizing to be a rather daunting one. It needn't be. The buyer simply needs to understand the sizing system used in the U.K. and what steps to follow to ensure the correct ring size. Knowing the correct size is especially important when shopping for a ring online using a platform like eBay.

What Is the Ring Size?

According to the International Standards Organisation (ISO), the ring size is a measure of the internal circumference of a ring, which is expressed in millimetres. However, many jewellers still use the internal diameter of the ring to determine ring size. Some European countries do use an internal circumference, but then deduct 4 cm from that measurement. Whereas, in the United States, ring size is measured in inches, or fractions of an inch. To confuse matters further, different countries use different scales, so their sizes are not readily interchangeable.

Ring Size Standards in the United Kingdom

In the United Kingdom, ring size is officially a measurement of the inner circumference of the ring, as contained in ISO 8653:1986. However, as mentioned above, many jewellers do not measure the internal circumference of the ring. Rather, they measure the diameter of the finger instead.

Size Chart

This leads to a situation whereby the size chart used in the United Kingdom, an extract of which is shown below, includes two measurements. The first measurement is the internal circumference of the ring, and the second is the diameter. Not surprisingly, many people find this confusing, and it is probably the source of much of the uncertainty that often arises when discussing ring sizes.

Ring Size






Internal Diameter (mm)






Internal Circumference (mm)






For purposes of keeping things simple, the chart extract above only shows whole sizes. The full chart actually has finer gradations, with half sizes that include P1/2, Q1/2, R1/2, and so forth. This sizing system is also used in Ireland.

Because a finger is long and thin and articulates at its joints, it important to keep the width of the band in mind when measuring for a ring. A ring with a wide band is one that is more than 8 mm wide, and it needs to be worn slightly looser. Therefore, for a ring with a wide band, the buyer should choose a ring that is half a size larger. Whereas a narrow ring, which is a ring with a band 7 mm wide or less,  needs to be worn slightly tighter.

Determining the Ring Size

A popular method for determining ring size is to use a piece of paper that is made into a paper ring. You simply make a ring, slips it on the ring finger, adjust it for the correct fit, and then you measure the internal circumference of the paper ring.

Unfortunately, the tolerances in determining ring size are small, which means an error of just a couple of millimetres can result in a measurement  that is two or three sizes astray from the correct size. Note that the difference between size P and size Q, for example, is just half a millimetre. Therefore, using the paper ring method is just too inaccurate a method to be of any real use.

Calipers and Measuring Rings

The only satisfactory way to measure ring size is to measure the ring using highly accurate calipers, in order to determine the internal diameter. When buying a ring online or by mail order, one should not only have the internal circumference but one should also have the more accurate, calipered measurement of the internal diameter of the ring. Therefore, it is important to visit a jeweller to be properly measured for ring size.

Jewellers often use steel measuring rings to determine ring size .These are carefully machined to set tolerances, and they can tell the jeweller exactly how large the finger is.


Jewellers often use mandrels, too. A mandrel is a calibrated measuring rod that is used to measure ring size instead of calipers. It is quicker and easier, and in the proper hand a mandrel is an accurate way to measure ring size.

Measure the Finger in the Evening

A small but important point when discussing finger measuring, is to remember that fingers swell during the day. Since the measurement needs to reflect the largest finger size, fingers should always be measured in the afternoon or evening, rather than the morning.

Where Best to Buy a Ring

The popularity of rings ensure that they are well represented in the high street. High street jewellers make a substantial profit from their trade in rings, and generally carry a fairly good range. However, high overheads on the high street, such as rent and local authority charges, mean that substantial costs must be passed on to the shopper. This raises prices. And although a good selection of rings is available, to see the breadth of variety in rings requires that a shopper visit half a dozen jewellers. The reality is that even the best stocked high street jeweller is limited as to how many rings they can stock.

For the best prices and the most extensive range, many shoppers choose to shop for rings online. eBay offers a much greater selection, often at better prices than the high street jewellers.

Finding a Ring on eBay

It is easy to find the ring you are looking for on eBay. Simply type in just a few words that best describe the ring you are looking for into the search bar on the eBay home page. For example, if you are looking for a ring for a man, type in 'men's rings '. This action brings up literally thousands of listings for men's rings of all types, including new and used rings, rings made gold or silver, and rings with gemstones and without. You can either browse the listings at your leisure, or you can narrow them down all the listings to more accurately reflect the characteristics you are looking for in a ring. This is easy to accomplish. If you want a ring which is made of  gold and has diamond setting, you can set the search filters such that only listings for gold, diamond rings appear on the results page. Of course, eBay also allows you to sort the listings by ring size.

When you have a handful of listings that interest you, read the descriptions carefully and study the photos. If you need more information, feel free to contact the seller via their profile page, and ask more information or even ask the seller for better photos of the ring listed for sale. It is worth noting that you can see feedback from previous buyers on the seller's profile page. The sellers with the highest feedback earn the title: 'Top-Rated Seller', and these sellers are likely to be especially helpful in meeting your requests for information.


The question of ring sizing is complicated by the fact that there is no consensus on the subject of sizing. Jewellers can vary on how closely they follow international standards, with some jewellers defining the rings size one way and other jewellers defining ring size another way. The International Standards Organisation has produced a standard, but it is not always applied. In the United Kingdom ring size is normally defined as either the internal diameter, or the internal circumference. This dual definition makes for a confusing ring size chart, and is the source of much uncertainty among shoppers. The best way to find the size of a ring is to use calipers to measure the fingers internal diameter. The best way to find the size of a finger is to use carefully machined steel jeweller's rings to measure the finger. This is best done in the evening, as fingers swell as the day progresses. Printing size guides out from the Internet is not an accurate way to take a ring measurement, and is not recommended.

When it comes to buying a ring, the high street can be expensive, due the overheads jewellers have to meet, with costs often passed on to the consumer. Online retailers such as eBay offer a wider choice and better prices, which makes eBay a good venue to search for a ring..   

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