drawing © 2004 iStockPhoto.com/ Sean Locke

ringsdrawing of rings

Share this page

Determining a person's ring size

The correct size depends, not just on the finger, but also on the ring. A wide ring will probably need to be a slightly larger size than a narrow ring. Finger size varies, even over the course of a few days: narrower in cold weather and wider in hot. It can also be affected by health. Like blood pressure readings, the most accurate result is found by taking a series of readings spaced over days and at different times of day.

The following ways of determining size are listed in descending order of reliability.

photo of a set of ring gauges

1. The best way is to visit a jeweler, who is likely to use a set of metal finger gauges such as those shown at right. He or she will also be able to take into account what sort of ring you are thinking of buying. Nowadays, if the intended wearer can't come to the shop, many jewelers give away disposable plastic gauges.

To use a set of finger gauges, try progressively smaller sizes until you come to a size that just won't go on. Then reverse course, trying larger sizes until you reach one that is comfortable.

2. Measure an existing ring that fits well. This method is more accurate if the width of the hoop of the new ring resembles that of the old.

3. (Not recommended) Measure by wrapping a very narrow, somewhat stiff strip of paper around the finger. A better alternative is a plastic cable tie, because you can try slipping it on and off, which you can't do with the paper.

Gauges that you download from the internet and print out can be very misleading. Between the net and the printer output tray are many points at which the computer (and/or printer) may be reducing or enlarging the image.

4. (Not recommended) The worst way is using a string. String is flexible and takes any shape; rings are stiff and nearly circular.

5. Guess. In some situations this is all you can do. Guess big, because it is easier to make a ring smaller than bigger. Women's ring fingers typically take a U.S. size 6 to 7. Or, arrange with the jeweler to exchange the ring for the right size after you have popped the question (but many women will not want to give up the very ring you proposed with).

Special difficulties

Some people have fingers that taper gradually from palm to fingertip; it is hard for them to retain a ring.

Resizing rings

A competent jeweler can resize most rings, and the resizing will be invisible to the naked eye. Success depends in part on what the ring is made of. Plain gold bands are the easiest rings to resize. White gold has often been plated with rhodium, perhaps with plated layers of other metals, such as nickel, beneath. It can be very difficult to replate the ring to match the original plating. Silver, because it is often rhodium-plated, can be problematical for the same reason. Platinum requires extremely high temperatures. Stainless steel and titanium rings are difficult or impossible to resize. Some rings cannot be enlarged because they contain an inset stone that would be stressed and possibly crack in use if the hoop were enlarged.

The technique used to resize the ring partly depends on how large a change is needed. If it is only a ¼ or ½ step (US sizes), machines exist that can actually stretch or compress the band, assuming there are no stones. Rings whose cross section varies widely cannot be stretched, because all the thinning would be concentrated in the parts of the band that are already thinnest. A technique often used on rings with stones involves a machine that uses rollers to roll out and thus lengthen the part of the band without stones. All these techniques unavoidably thin the band somewhat.

If a greater change in size is required, the shank will be cut and a section removed or a new section inserted. This is not as alarming as it sounds. In fact, a great many rings are manufactured with a join in the first place, and the jeweler will open the shank at the same point.

To enlarge a ring, the shank is cut and a piece of new stock is soldered in place. If the ring has been previously resized larger and already has two joins, the jeweler will remove the previously inserted piece and insert in its place a new, longer piece. The resized ring will thus continue to have two and only two, joins. The quality depends on workmanship (how well the cut ends were rendered plane, parallel, and aligned), and upon how closely the metal of the new piece matches the original alloy used in the ring. A large shop is likely to have a greater selection of alloys than a small one.

In the latest equipment, a laser substitutes for the torch, and solder is unnecessary. The heat is so intense and focused that the metal melts and flows together.

When picking up a resized ring, examine it closely. It should of course be clean, completely free of the abrasives used in repolishing. Other than that, on examining both the inside and outside surfaces, you simply don't want to be able to tell the ring was resized. That means the shank has a uniform, consistent shape and color, and there are no pitmarks or other depressions to reveal the location of the join. And it should fit. If there is any doubt in your mind that the size specified has been achieved, ask if you may test the ring on the jeweler's tapered steel mandrel.

resource

Advice on resizing from a seller of titanium rings. Notice their offer to replace a newly-bought ring with one of a different size.

Ring size systems

Download and print the chart. Even if you do not need to convert between the different national ring sizing systems, the chart is an easy way to read off inside circumference and diameter in inches and millimeters.

To convert a size in one system to a size in another, look up the circumference in millimeters of the size that fits. Then find the smallest size in the system you wish to convert to that has a circumference at least equal to the first circumference.

United States ring sizes

Quarter-sizes (for example, 6¾), intermediate between the whole and half sizes, are also used, and sometimes even eighth sizes (e.g., 6 5/8).

American Ring Sizes
Size Inside measurement
in inches
Inside measurement
in millimeters
diameter circum-
ference
diam. circum.
½ 0.474 1.489 12.0 37.8
1 0.490 1.539 12.4 39.1
0.506 1.590 12.9 40.4
2 0.522 1.640 13.3 41.6
0.538 1.690 13.7 42.9
3 0.554 1.740 14.1 44.2
0.570 1.791 14.5 45.5
4 0.586 1.841 14.9 46.8
0.602 1.891 15.3 48.0
5 0.618 1.942 15.7 49.3
0.634 1.992 16.1 50.6
6 0.650 2.042 16.5 51.9
0.666 2.092 16.9 53.1
7 0.682 2.143 17.3 54.4
0.698 2.193 17.7 55.7
8 0.714 2.243 18.1 57.0
0.730 2.293 18.5 58.2
9 0.746 2.344 18.9 59.5
0.762 2.394 19.4 60.8
10 0.778 2.444 19.8 62.1
10½ 0.794 2.494 20.2 63.3
11 0.810 2.545 20.6 64.6
11½ 0.826 2.595 21.0 65.9
12 0.842 2.645 21.4 67.2
12½ 0.858 2.695 21.8 68.5
13 0.874 2.746 22.2 69.7
13½ 0.890 2.796 22.6 71.0

The origin of American ring sizes is unknown. A U.S. patent for a ring gage, issued to F. E. Allen on February 3, 1874, shows ring sizes from 1 to 13 with quarter sizes, so the system was in use by then. In the 1920's the National Bureau of Standards surveyed the ring gagesĀ¹ in use at a nationwide sample of jewelers and discovered the same size numbers were being used for different dimensions. This appears still to be the case.

1. U.S. Dept. of Commerce, National Bureau of Standards.
Jeweler's and Silversmith's Weights and Measures (2nd ed).
Bureau of Standards Circular 43.
Washington, D.C.: U. S. Government Printing Office, 1921.

Page 39.

British ring sizes

The earliest British scale appears to have had steps of 1/64th inch in diameter, but the 1949 British Standard had a whole size steps of 0.0155 inch of diameter (1/64th inch is 0.015625 inch). Some sources say the scale begins at 0 = an inside diameter of 0.4595 inch.

A new standard was issued in 1987. It retained the names of the sizes but otherwise was more European: millimeters instead of inches, and circumference, not diameter. Each whole step is an increase of 1.25 mm in circumference. The largest difference between the old and new scales is 0.0051 inches, which is negligible.

British Ring Sizes
  BS6820:1987 BS1283:1945 (obsolete)
Size Inside
diameter
Inside
circumference
Inside
diameter
Inside
circumference
inches mm inches mm inches mm inches mm
A  0.4699 11.94 1.476 37.500 0.4750 12.065 1.493 37.9
0.4778 12.14 1.501 38.125 0.4828 12.263 1.517 38.5
B  0.4856 12.33 1.526 38.750 0.4905 12.459 1.541 39.1
0.4934 12.53 1.550 39.375 0.4983 12.657 1.566 39.8
C  0.5013 12.73 1.575 40.000 0.5060 12.852 1.590 40.4
0.5091 12.93 1.599 40.625 0.5138 13.051 1.614 41.0
D  0.5169 13.13 1.624 41.250 0.5215 13.246 1.639 41.6
0.5248 13.33 1.649 41.875 0.5293 13.444 1.663 42.2
E 0.5326 13.53 1.673 42.500 0.5370 13.640 1.688 42.9
0.5404 13.73 1.698 43.125 0.5448 13.838 1.712 43.5
F 0.5483 13.93 1.722 43.750 0.5525 14.034 1.736 44.1
0.5561 14.13 1.747 44.375 0.5603 14.232 1.761 44.7
G 0.5639 14.32 1.772 45.000 0.5680 14.427 1.785 45.3
0.5718 14.52 1.796 45.625 0.5758 14.625 1.809 45.9
H 0.5796 14.72 1.821 46.250 0.5835 14.821 1.834 46.6
0.5874 14.92 1.845 46.875 0.5913 15.019 1.858 47.2
I 0.5953 15.12 1.870 47.500 0.5990 15.215 1.882 47.8
0.6031 15.32 1.895 48.125 0.6068 15.413 1.907 48.4
J 0.6109 15.52 1.919 48.750 0.6145 15.608 1.931 49.0
0.6188 15.72 1.944 49.375 0.6223 15.806 1.955 49.7
K 0.6266 15.92 1.969 50.000 0.6300 16.002 1.980 50.3
0.6344 16.11 1.993 50.625 0.6378 16.200 2.004 50.9
L 0.6423 16.31 2.018 51.250 0.6455 16.396 2.028 51.5
0.6501 16.51 2.042 51.875 0.6533 16.594 2.053 52.1
M 0.6579 16.71 2.067 52.500 0.6610 16.789 2.077 52.8
0.6658 16.91 2.092 53.125 0.6688 16.988 2.101 53.4
N 0.6736 17.11 2.116 53.750 0.6765 17.183 2.126 54.0
0.6814 17.31 2.141 54.375 0.6843 17.381 2.150 54.6
O 0.6893 17.51 2.165 55.000 0.6920 17.577 2.175 55.2
0.6971 17.71 2.190 55.625 0.6998 17.775 2.199 55.9
P 0.7049 17.90 2.215 56.250 0.7075 17.971 2.223 56.5
0.7128 18.10 2.239 56.875 0.7153 18.169 2.248 57.1
Q 0.7206 18.30 2.264 57.500 0.7230 18.364 2.272 57.7
0.7284 18.50 2.288 58.125 0.7308 18.562 2.296 58.3
R 0.7362 18.70 2.313 58.750 0.7385 18.758 2.320 58.9
0.7441 18.90 2.338 59.375 0.7463 18.956 2.345 59.6
S 0.7519 19.10 2.362 60.000 0.7540 19.152 2.369 60.2
0.7597 19.30 2.387 60.625 0.7618 19.350 2.394 60.8
T 0.7676 19.50 2.411 61.250 0.7695 19.545 2.418 61.4
0.7754 19.70 2.436 61.875 0.7773 19.741 2.442 62.0
U 0.7832 19.89 2.461 62.500 0.7850 19.939 2.467 62.7
0.7911 20.09 2.485 63.125 0.7928 20.137 2.491 63.3
V 0/7989 20.29 2.510 63.750 0.8005 20.333 2.515 63.9
0.8067 20.49 2.534 64.375 0.8083 20.531 2.540 64.5
W 0.8146 20.69 2.559 65.000 0.8160 20.726 2.564 65.1
0.8224 20.89 2.584 65.625 0.8238 20.925 2.588 65.7
X 0.8302 21.09 2.608 66.250 0.8315 21.120 2.613 66.4
0.8381 21.29 2.633 66.875 0.8393 21.318 2.637 67.0
Y 0.8459 21.49 2.657 67.500 0.8470 21.514 2.661 67.6
0.8537 21.68 2.682 68.125 0.8548 21.712 2.686 68.2
Z 0.8616 21.88 2.707 68.750 0.8625 21.908 2.710 68.8
0.8694 22.08 2.731 69.375 0.8703 22.106 2.735 69.5
Z+1 0.8772 22.28 2.756 70.000 0.8780 22.301 2.758 70.1
Z+2 0.8929 22.68 2.805 71.250 0.8935 22.695 2.807 71.3

British Standard BS6820:1987.

British Standard BS1283:1945.
Jewellers' ring sticks and ring gauges.

This standard is withdrawn.

Japanese ring sizes

The scale begins at 0 = an inside diameter of 13 millimeters; a whole size step is an increase of one-third of a millimeter in diameter.

Change any value, then click outside the boxes to calculate.
Ring size (from 1 to 27): .
Inside diameter in millimeters is .
Inside circumference in millimeters is .

European ring sizes

In the most common system, the size is simply the inner circumference in millimeters; typical sizes fall roughly in the range 38 to 69.

French ring sizes

The size is the inner circumference in millimeters. Half and quarter fractional steps are used.

German ring sizes

An older German system, in whole, half and quarter steps running from about 13¼ to 22, was simply the inner diameter in millimeters.

Polish ring sizes

The most popular ring size system in Poland starts with size 1 at 12.666 millimeters and increases in increments of 1/3 millimeter. So size 1 is 12.666 mm, size 2 is 13.00 mm and so on.  Size 33 is 23.33 mm.

Swiss ring sizes

The inner circumference in millimeters, minus 40.

Yet other sources describe the Swiss sizes as the inner diameter in millimeters plus 40. If you have personal knowledge of Swiss ring sizes, please write us.

resources

Antoinette Mattias and Antonio C. Bonanno.
Engagement & Wedding Rings. 3rd Ed.
Woodstock (VT): GemStone Press, 2003.

home | people index | search |  contact drawing of envelope |  contributors | 
help | privacy | terms of use