Ring Size Chart and Guide

How to measure ring size

The most accurate way to determine your ring size is to visit a local jewelry store where they have several measurement tools to determine your ring size. If you have a ring that fits well and you need to find out the size, a steel ring mandrel is used. The ring is placed on the ring mandrel and the number on the mandrel that corresponds with the bottom of the ring is the ring size. Below is a picture of a ring mandrel.


Ring mandrel

Ring mandrel tool used to determine ring size. Slide ring on mandrel and read the size at the bottom of the ring.


Another jeweler’s tool used to measure ring size are metal ring sizers. This is a ring that holds all of the different ring sizes in increments that range from every quarter size to every half size, depending on the tool, so that you may try on the ring to determine which ring size fits you the best. The ring sizers come in a narrow width and a wide width to accurately determine your ring size, since a ring’s width affects the size of the ring that is most comfortable for you.


Metal ring sizers in narrow and wide width to measure ring size.

Metal ring sizers in narrow and wide width to measure ring size.


Printable Ring Sizer

Below is a ring size chart that can be used to determine the size of a ring. To determine the most accurate ring size, the ring should cover the circle so that the black circle touches the inside of the ring. Please note that although you may use this ring sizer to get a fairly accurate measurement of your ring, it is always advisable to have your ring sized by a professional jeweler using one of the professional tools shown above – a ring mandrel or a ring sizer – to determine the exact size of your ring.

If you would like to use a more substantial and accurate ring sizer at home, ring mandrels and ring sizers are available for sale at a crafts store like Michaels or Joann, or you can find a wide selection on Ebay and Amazon. It is recommended to buy a metal ring sizer, not a plastic one, since it is most similar to a metal ring.

Please note that when using the ring size chart below, there are many factors that can affect the accuracy of your measurements. The image should print at 100% and you should verify the accuracy of the ring size chart by confirming that the line shown on the chart measures 125mm. You are also matching up the ring to the circle by eye, which isn’t 100% accurate.

Ring Size Chart

Ring Size Chart

Below is a ring size chart that specifies the diameter of the ring (the measurement across the ring) and the circumference of the ring (the measurement around the ring) for each size. The measurements are given in both inches and millimeters, however, the metric system of millimeters is much easier to use with a standard ruler. The difference in the diameter between each whole ring size is .8mm and each half ring size is .4mm.




Ring SizeDiameterCircumferenceDiameterCircumferenceUK Sizing
515.749.30.6181.94J 1/2
5.516.250.60.6341.99K 1/2
616.551.90.6502.04L 1/2
>6.516.953.10.6662.09M 1/2
717.354.40.6822.14N 1/2
>7.517.755.70.6982.19O 1/2
>818.157.00.7142.24P 1/2
8.518.558.30.732.29Q 1/2
919.059.50.7462.34R 1/2
9.519.460.80.7622.39S 1/2
>1019.862.10.7782.44T 1/2
10.520.263.40.7942.49U 1/2
1120.664.60.812.54V 1/2
11.521.065.90.8362.59W 1/2
>1221.467.20.8422.65X 1/2

Factors in how to determine ring size.

There are many factors that determine your ring size, which can change from day to night and season to season, as follows:

  • Temperature – Fingers have a smaller diameter in cold weather and a bigger diameter in warm weather
  • Humidity causes fingers to swell
  • Diet – Salt and other foods can cause you to retain water and swell
  • Weight loss or gain
  • Exercise
  • Pregnancy
  • Time of Day – Fingers tend to be a smaller diameter in the morning and bigger at night.

It is advised to have your finger sized in the middle of the day in a room that is room temperature.

Ring resizing – How to resize a ring to make bigger or smaller.

A valuable ring should always be resized by a professional jeweler. A simple ring with no stones can be made approximately one size larger by hammering it down on a mandrel to stretch the ring. If it needs to be made much larger than one full ring size, it will need to be cut open and a matching metal needs to be welded into the ring to expand it. It will then be polished so that the cut will be virtually invisible.

To make a ring smaller, a small piece of metal needs to be removed from the ring, and then it will be welded back together and polished.

A ring with stones must be carefully sized to avoid crushing the stones if the ring is made smaller. If the ring is made bigger, the settings that hold the stones will be expanded so the stones may fall out.

A ring guard may be used to make a ring smaller, but this is not a long-term solution for a cherished or valuable ring. A plastic ring guard can fall out, or may require glue to hold in place. A metal ring guard is made from flexible metal and will bend or fall apart with constant wear of the ring. The ring guard can also been seen from the outside of the ring, so it is not very attractive.



Metal ring guard