CATHOLY Classic Flat Tungsten Carbide Ring with Engraved Cross Pattern

5. Visual Ring Width Guide

Most ring widths are measured in millimeters or “mm” for short, even in countries that use inches, such as the USA. Most people already have a hard enough time trying to imagine how wide a quarter inch or a half inch is. So, it is much more difficult to imagine how wide 6 mm is when you don’t even think in terms of the metric system to begin with. Customers frequently struggle with how wide they want their ring or wedding band to be. Below is a chart that shows common ring widths in millimeters converted to inches. If you have a ruler handy, you could reference it to easily visualize how wide the ring you are about to order will be.

If you don’t happen to have a ruler nearby, an everyday object we have found that gives an accurate representation of the width of a ring is a 5¢ US nickel. The thickness of a nickel is basically 2 mm thick.

How wide is a 2mm ring?

A 2mm ring is as about the width of a nickle. Standard U.S uses nickle measures 1/16 of an inch, which is almost 2mm wide.

How wide is a 6mm ring?

An 6mm ring is as about the width of three nickles stacked together. A standard U.S uses nickle measures 1/16 of an inch, which is almost 2mm wide. Three nickles, or 6mm, would measure 6/16 inch.

How wide is an 8mm ring?

An 8mm ring is as about the width of four nickles stacked together. A standard U.S uses nickle measures 1/16 of an inch, which is almost 2mm wide. Four nickles, or 8mm, would measure 1/4 inch.

6. MM to Inch Width Conversion Chart

7. Comfort Fit Sizing Information

North America There are two types of sizing systems in North America: Standard Fit and Comfort Fit. Standard fit rings and wedding bands are the most common types. Comfort Fit is newer and not as well known as Standard Fit.

Both types of fit are explained below.

International Sizing. If you live outside of North America, you can go to a jeweler near you to get your finger measured. Then, go to our international ring size conversion page to find the correct US ring size to order. Or, if you can find out the diameter or circumference of your ring size in millimeters, we will be able to convert it to the proper US size as well.

Comfort Fit

This type of fitting is defined as a ring that is domed in the interior (where the ring touches the finger), instead of flat, like Standard Fit. The diameter at the exact middle of the ring (between the two edges) is smaller than the diameter at the edges of the ring. This type of fit is most commonly used in rings that are difficult to resize, such as tungsten, ceramic, cobalt chrome and titanium. This is why tungsten rings commonly have lifetime replacement programs for sizing, similar to Larson Jewelers’ industry leading no fee lifetime sizing warranty for tungsten wedding bands. The advantages of Comfort Fit are the ring slides over the knuckle easier and the ring creates less friction because it covers less skin surface area.

Determining Comfort Fit Size:

A good method of determining your Comfort Fit size is to first determine your Standard Fit size at a local jeweler (explained below), and then order a half size smaller. For example, if you are measured for a Standard Fit size 9.0 by your local jeweler, you should order a Comfort Fit size 8.5. This is simply a general recommendation, not a hard rule. For rings that are wider than 8 mm, it is not recommended to go down half a size because rings wider than 8 mm fit tighter. Ring sizes are a bit like shoe sizes and differ slightly from manufacturer to manufacturer. This is why different jewelers may measure your finger at slightly different sizes.

Standard Fit

This type of fitting is defined as a ring that is flat along the interior of the ring (where the ring touches the ring finger). This is easiest to illustrate by comparing the interior of the ring to the interior of a pipe, it is the same diameter from one edge to the other. This type of fit is most commonly used in precious metal rings such as platinum, palladium, and white gold. Although it is slightly less comfortable to wear when compared to Comfort Fit, Standard Fit is definitely not “uncomfortable”. Standard Fit has been used in the jewelry industry for centuries.