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UK sizing versus US sizing?


Hi all – I’ve been trying to figure out the accurate size
conversion from UK to US sizing. I have been looking up online charts
to see what ‘N’ is and come up with a range of sizes from 6.5 to 7
(and giving a circ. difference of ~2.5mm)… It’s only 1/2 size
difference but it makes a difference when gauging wide wedding bands
and I’m kind of freaking out a little about what to do (my rings
can’t really be sized once finished). Does anyone have any direct
experience with UK & US sizes or have a UK/US mandrel/sizer to
compare directly? This is the sizing chart I’m deciding upon using:

Can anyone verify this as accurate? --thanks! cheyenne


Try this one, to verify yours, or you can use this one :wink:

Regards Charles A.


Hello Cheyenne,

My chart says N = size 6.75 (diameter 0.674 inches or 17.1 mm)

You would think this was an easy question. But since there are no
less than four measurement systems in play and on top of that
jewelers cannot agree if they should measure to the edge of the ring
or to the center it is difficult to get a straight answer.

More than 10 years ago an employee of mine that was a mathematician
made a chart that is at More
accurate than most and within the margin of error that is reasonably

Wide rings are a special problem, since it is common to read the
ring gauge or mandrel to the center of the ring to compensate for the
greater friction that is characteristic of a wide ring. If you do
this you will have the “feel” of the size but actually a greater
inside diameter. Have a look at the “reality check” below the chart.

Good luck,
Stephen Walker


as suggestion – buy a set of ring sizers from UK, then just size
the finger with the UK sizers.




As far as I know (anyone, please correct me if I’m wrong) there is
no legal nor defined industry standard for ring sizes, therefore
anyone can use any sizing regime they wish. There may be sizes that
are traditional and customary, but those aren’t writ in stone, and as
I’m sure you’re aware now, there are many size charts with minor to
major variations among them.

The decision I’ve come to is that the only correct ring size is the
one that properly fits your customer to their satisfaction. As far as
mandrels and rings sizers, those made by different manufacturers (or
even by the same manufacturer) are frequently out of synch. It’s
often found that your sizers don’t match up the rings on your

Select size dimensions that work for you, then stay with it unless
there’s a compelling reason to change.

On a tangent, I wonder if we Orchidians couldn’t devise and make
available for use a common size chart thereby establishing some
accepted standard, if only among ourselves, and of course by
individual choice, not decree. Any thoughts/comments (hahaha do I
really need to ask?)

Mike DeBurgh, GJG
Alliance, OH