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International Ring Size Equivalents

I am finishing a book called Professional Ring Repair, which
should be out in a couple of months. As part of the Appendix, I
plan to include a table on international ring size equivalents.
However gathering accurate and complete on this
subject has eluded me so far. Any assistance in this direction
would be greatly appreciated. Thank you. Alan

I’ve noticed a lot of fairly broad statements made about
equivalent sizings, and it’s a worrying trend.

I suggest bringing all the sizes down to a common physical
diameter. Metric, I hasten to suggest as well, as it’s an
accurate and universal system.

Translate all ring size systems to mm, and so a ring size in the
American system will be a certain mm diameter, and therefore the
equivalent size in any other system may be easily ascertained.

Just my 2c worth!

B r i a n A d a m J e w e l l e r y E y e w e a r

   I am finishing a book called Professional Ring Repair,
which should be out in a couple of months. As part of the
Appendix, I plan to include a table on international ring size
equivalents. However gathering accurate and complete
on this subject has eluded me so far. Any
assistance in this direction would be greatly appreciated.

Alan, Just today, a poster on sent the
following message to the group. Probably, he’s not got much that
you don’t already have, but for what it’s worth, here 'tis. You
might also check past posts the last couple weeks on the subject,
as it was a bit of a discussion topic for a while, after
someone, just before christmas needed some conversions. It’s
interesting that some of the responses varied a bit, from
presumably reliable sources. I assume, also, that you’ve already
got Knuths chart from his book…

Peter Rowe

       Hi All, Due to the numerous requests for ring size
       conversions that I have seen come through this group
       over the last couple of months, I have put together a
       nice table that incorporates most of the major sizing
       methods.  The table includes American, British,
       French, German, Japanese, and swiss charts. Also
       included is an equivalent inch diameter chart. If
       anyone else asks questions about conversions, at least
       now we have a place to send them. 

       *I must note that the chart that I have made was
       developed from a chart taken from the back of one of
       my suppliers catalogs.

Hi Alan,

There is a complete comparison table in “Jewelry Concepts and
Technology” by OPPI UNTRACHT.

I think I abstracted the table a year or so ago and it may be in
the archive.

Good luck with the book.


Kerry McCandlish Jewellery - Celtic and Scottish styles
Commission/Custom Work undertaken…
Katunayake, Creagorry, Isle of Benbecula, HS7 5PG SCOTLAND
Tel: +44 1870-602-677 Fax: +44 1870-602-956 Mobile: +44 850-059-162

Hi Alan, There is now an ISO standard for ring sizes. I believe
I have a chart at the office listing them and many of the
European and Asian equivalents these standards are replacing. I
researched this about a year ago and was surprised to learn that
the American ring sizes we all go by were elminated in the 50’s
(I think) by the government agency that had originally
standardized them. Technically speaking the ring sizes we use
today in the states, we use by popular consent only because there
is no law or officially recognized US standard anymore. Hence
the nightmare variation in ring sticks and sizers.

I will fax you all the info I have tomorrow (Monday) when I am
back at the office.

I wonder if industry leaders such as yourself, Gesswein, and
others shouldn’t organize ourselves and approach the Jewelers
Vigilance Committee (or other appropriate board) to propose
either formalizing the current US ring sizes once again - or - to
suggest the adoption of new standards such as the ISO standards.

Wouldn’t it be wonderful to end the confusion over ring sizes?
What do you think Alan? This could be relatively easy - all we’d
need to do is draft a letter and get signatures. The hard part
will be getting everyone to agree on what the standards should
be. :slight_smile:

I would love input on this idea from anyone on Orchid who wants
to give it.

Best Regards and Happy New Year!

Elaine Corwin
VP Tech Services
Bridgeport CT 06605
Phone: 1-800-544-2043, x287
Fax: 203-335-0300
Direct Email: @ElaineEC

Brian, That’s a breath of fresh air - I think already in small
metric like most jewelers and folks that work on thier cars so
iits no great leap to think mm for sizes. Do you already
correspond to mm to size? I’ll throw in my two millimeters!

Alan, I asked the same question a while ago on - here is where I was pointed: Also someone
sent me a chart that is available from the GIA. It is the most
complete. If you can’t find it, email me and I will send you a
copy via snail mail.

Jan McClellan

Obviously using a standard like metrics will do it. And any
thinking person would not use any other system. But they do and
that is what I want.

Thanks for thinking about it, but I want to compile an accurate
and reliable chart for those not yet enlightened. The US was the
first country to have metric money, which Alexander Hamilton,
then Secretary of the Treasury introduced in 1789. Now we are the
last industrialized country to keep using the silly English
system for measurement of everything from gasoline to ring sizes.

Hi Elaine,

Great idea!

Any time there is a standard for anything it creates confidence
in the finished product for the end user. It also simplifies the
manufacture, marketing & repair of the item because now everyone
is talking the same language.

I’d suggest that the easiest way to get acceptance in the US
would be to keep what is currently in use. However, the sizes
should be defined in terms of fractions of an inch (decimal size
8= .713" or 18.1mm etc). The other than round shapes could be
defined with the standard sizes but with corner to corner &
widest length & width dimensions.

This scheme would not require anybody to spend money for new
tools or require learning a new system (some folks refuse to
learn or change).

A project like this could be ‘pushed’ by the various trade
groups within the industry (MJSA, JVC, SNAG, AGS, etc).


Elaine and others on Orchid: The confusion over ring sizes is
disappointing. Why we use the anachronistic system we do, which
has no basis in reality, only digs us deeper into isolation and
oblivion, when the US should be a leader among the jewelry super
powers. As a proponent of metrics, I would opt for that, the
most logical of systems. However, trying to get Joe Jeweler in
Jersey to join is another story.

Give me the petition and I will sign it.

Alan Revere
Revere Academy of Jewelry Arts
San Francisco

Hi Folks, Has anyone else on this list had as bad of a negative
reaction to the metric system as I have? My Dad and my cousin
and my good friend are all tool and die makers here in the U.S.
The mere mention of the metric system brings steam out of their
ears! I hear every excuse under the sun why metric stinks,
“It’s easier to deal with thousandths”!!! Duh! What do you
think the metric system is? I have experienced this with
clients also. There is an old saying, “you can’t teach an old
dog new tricks”. I am beginning to think that if the dog is too
old to learn new tricks, it was probably always too ‘old’ to
learn! It’s kinda like the whole world is wrong and they are
right, mentality.

Clients have a hard time understanding, say, 2 or 2 1/2 or 3mm
side stones with an 8 x 10 mm central stone. They will
invariably say “yes but how big is the central stone?”. I
sometimes think that it would be an easier task to get the world
to change to inches and feet than to educate most of the
Americans to the metric system! Sounds like the old dog… to
me! Any suggestions?



Skip Meister
N.R.A. Endowment &
Certified Instructor
in all disciplines
Certified Illinois D.N.R.
Hunter Ed, Instructor

Regarding “other than round” shapes, using corner to corner
won’t work well, since even a subtle difference in the profile,
even if it fits the same on a finger, will change that dimension.
I’d suggest using a circumference equivalence, so that for
example, a semi square size six would have the same circumference
as a standard round size six. The important point would be that
the size numbers do not mean that a size six that fits when
square would automatically fit when in a round ring. Doesn’t
quite work that way. You simply need to measure the finger with
sizers matched to the ring profile for real measuring accuracy.
But specifying the size with circumference lets you use things
like flexible mandrels, rubber, or paper if you don’t have an
exact match steel mandrel. (make a flexible mandrel by wrapping
paper around a standard mandrel and taping together. Slide a
size six sizer on and mark where it fits on the paper. slide
paper mandrel into non round ring, and it measures where the
circumferences match… Actual finger fit then has to be
estimated by comparing the measured size of the existing ring
with a similar circumference round sizer, and extrapolating…
Cumbersome, but it does, after a fashion, work.

What that means is that while it’s fine to specify the easy to
measure diameter of a round ring for a give size, the actual
specification would be for the circumference defined by that
diameter. Which is, of course, what the european systems already
do, only in metric measurements…

Peter Rowe

I agree 1000%; there are a lot of ‘mental old dogs’!

Many times visualizing something is a matter of experience. Most
folks who’ve not worked around any precision measurement
(thousandths of an inch, tenths of a mm or grams etc.) don’t have
any frame of reference. I’d suspected a lot of lay people would
have a hard time making an accurate visualization of 5/16 x
25/64 or .315 x .390(aprox 8x10mm) stone as well.

Probably the best thing any of using metric (or other uncommon)
measurement systems could do is to translate the dimension into
something a lay person could relate to. FWIW, 1" = 25.4, 1 mm =
.039 in (rounded to nearest .001), just a little (.00875) over 1
/32". If possible, having a display (ruler calibrated in both
english & metric) might help them understand if they’ve got an
open mind.

Until everyone has looked at & used the metric system long
enough to have fixed the relative sizes in their mind they won’t
be able to accurately visualize items specified in metric terms.

My 2 mm worth.


Hello Alan,

Good luck in your metric proselytising. The Metric system has
been the official standard of measurement for over 130 years in
the USA, I’m sure it will catch on soon. In my experience I have
noticed that those who refuse to embrace the quintal and the
myriametre invariably can’t tell you what a cran or hogshead is
either. Ignorance breeds stupidity. Stupidity breeds

As an aside Great Britain’s Imperial system is not used in the
USA. The silly parts are all American inventions, such as funny
ring sizes, the short gallon and the short ton. The
inappropriate application of Imperial measurements used in the
American system completely defeats its advantages. For instance
if you read a manifest that states;

a)   1000 carats  
b)   1000 Troy ounces  

You would know that you have precious gems and precious metals
without having to individually identify them. The Imperial system
used correctly will allow this with all commodities.

May your firkin be forever full…Tony.

(1) The United States was an original signatory party to the
1875 Treaty of the Meter (20 Stat. 709), which established
the General Conference of Weights and Measures, the
International Committee of Weights and Measures and the
International Bureau of Weights and Measures.
(2) Although the use of metric measurement standards in the
United States has been authorized by law since 1866 (Act of
July 28, 1866; 14 Stat. 339), this Nation today is the only
industrially developed nation which has not established a
national policy of committing itself and taking steps to facilitate
conversion to the metric system.

\ () || |/
\ /
web site:

Vancouver, B.C. CANADA.

  There is an old saying, "you can't teach an old dog new
tricks".  I am beginning to think that if the dog is too old to
learn new tricks, it was probably *always* too 'old' to learn! 

G’day; a few thoughts on ring sizes and metrication. New Zealand
went entirely metric about 35 years ago, after using the
Imperial system we had all been brought up with; for the majority
of NZ-ers are of British descent. There was a monumental outcry
and outrageous screaming tantrum at the time. People swore
they’d refuse to use it. But the money was changed too. No
longer did we have to calculate 4 farthings to a penny, 12
pennies to a shilling and twenty shillings to a pound. (Guineas
had gone before I started school) We exchanged it all for
dollars and cents, like America etc. (only many of us wish it had
been called something other than dollars - like ‘Kiwis’ for
instance? Very shortly after, pounds, shillings and all
Imperial measurements were phased right out over a period, and
all the shopkeepers had to get their cash tills changed, their
weighing machines, rulers, and tape measures, scrapped, and
to try and think in the ‘new’ measurements. It was difficult
for many people, and even I who served in laboratories using
metrics all my working life, found it hard to change when it came
to everyday things. Many used both systems. But change we all
(to a certain extent - I still think room temperatures in
Fahrenheit, yet furnace temperatures in C.!) But people out
shopping buy meat by the kilo, fabric by the metre, wine by the
litre, and milk at 650 mls per bottle without hankering after
the old system. And the artisans settled down quicker than
most. (They had to!) No longer did they have to think, “3 3/8
plus 7 5/16 plus 1 1/4 subtract 4 27/32…etc.” In the
pre-metric days children had to learn: 4 gills one pint, two
pints one quart, 4 quarts one gallon…etc. 12 inches one foot,
three feet one yard, 22 yards one chain, 1760 yards one
mile…etc. Wacky, wasn’t it? Well. isn’t it? Not any longer
for my grandchildren. They never knew anything else other than
metrics. What I hope to convey to you is that it was an upheaval
at the time - but we wouldn’t change back. However, we still use
British ring sizes which are alphabetical, ‘K,L,M,N,O,P,’ etc,
but if we have to measure the metal to be used, why, we measure
the internal diameter of the sizers - in millimetres of course.
And that isn’t as confusing as it sounds either. But I would like
those to be graduated in metrics too. Try it; you’ll like it!
(Eventually!) Cheers, –


At sunny Nelson NZ

Skip: I remember well the early-mid 70’s when the last push was
on for conversion here in the States. A total failure because
they insisted upon comparing the two systems. A sudden and
complete changeover is called for. There’ll be much weeping,
wailing and nashing of teeth but they’ll get over it. (and be
better off too!)

Steve Klepinger

Hi Skip,

In Canada we went through the conversion experience in the late
70’s early 80’s. The basic problem is that you can’t use both
systems at the same time. If you are doing metric you have to use
metric tools, machine tools etc. If you are doing standard inches
etc. you have to stick with that. I was doing a diploma in
mechanical engineering technology when the big switch was going
on so I learned both systems. I sympathize with anyone trying to
use standard machine tools to produce metric items - it just
doesn’t work.

Once you wrap your head around not trying to convert back and
forth and working in one system or the other it is no big deal.
For some items metric makes sense such as science or engineering
since the units are more rational (say kilopascals versus pounds
per square inch). For linear measurement it makes no difference
really as long as the material, tools, and design are all in one
system or the other.

A visual comparison chart helps sometimes - using common items
ie. a sugar cube is about 15mm, an big orange about 100mm, a seed
bead about 2mm. If it is too much for them try explaining gun
calibers or carat weight ; ). The other trick is to have a side
by side ruler - two number lines right beside each other so they
can match metric to standard. I seem to remember Ford doing this
in some of their technical documentation when they started
slapping european engines in domestic cars.

By the by - although Canada is officially metric pretty much all
domestic automotive parts are still in inches and most products
have standard and metric labelling. It has created a bit of a
rift between generations - the older people can’t visualize
metric and the younger people can’t understand fractional inches
(Lets not even get into the concept of having two offical
languages and you would love our new gun laws). Since our
biggest trade partner is still the US most manufactured goods use

Hope this helps, and you really meant to say 2.5mm not 2 1/2mm
didn’t you ; )

Cameron Speedie
Isalnd Gem and Rock

Dear Allan, Sorry to be so late with a response, but I am a
thousand messages behind in orchid and will never catch up… in
Central Florida I am still under the Season rush for another 3
months… I have 17 pages of reference material on what you
require ( I believe ) but it is taken from 3 separate publication
of the Horological Times…( I assume I should not scan and post
it on Orchid ) or maybe it is allright…I do not know)

The material was published by Peter Kinberger and is exhaustive
as related to this subject. I will mail you a copy for your
as I presume this would be O.K. .

E-mail your working address and I will get it to you via US mail


Terry Parresol

 The US was the first country to have metric money, which
Alexander Hamilton, then Secretary of the Treasury introduced
in 1789. Now we are the last industrialized country to keep
using the silly English system for measurement of everything
from gasoline to ring sizes. 

the metric system was legalized for trade while Thomas Jefferson
was president. Technically, the english measures have never
been authorized. Just a weird tidbit of info.

Dan and Laura at Birdwalk Farms