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jump rings Ring Sizes - This page includes several conversion tables and explains my numbering system.

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Chainmaille Jump Ring Sizes

When purchasing jump rings, it is important to note how they are measured, as everyone does it differently. Some places measure the inner diameter of the ring, others use the outer diameter. Some prefer inches, some are metric and others combine both systems! Adding to the confusion, wire gauges are not consistent across metal types. You should always ask your suppliers for the exact measurements of their rings after springback to ensure you are buying what you need. (If you are not familiar with springback, it is explained in the Common Terms article.)

chart of base metal ring sizes Base Metal Jump Ring
Sample Sheet

For my rings:
Letter = Inner Diameter
Number = Wire Gauge

Chart for silver jump ring sizes Sterling Jump Ring
Sample Sheet

Inner Diameter

I thought Spider's numbering system was ingenious, and though she has a new numbering system, I have adopted her old method for the rings I sell. This means that each ring has a letter (corresponding to the inner diameter) and a number (corresponding to the gauge).

To understand exactly what the letters mean, please refer to the chart below. Letter A rings are smaller than B, which are smaller than C, and so on. The letters refer to the size of the mandrel that the raw wire was wrapped around. To find the exact inner diameter (ID), after springback, of each ring I sell, look at the stats/uses pages in the supplies section.

I use letters, because many people find it easier to understand that a sequence of increasing inner diameters is F, G, H rather than 5/32, 11/64, 3/16. If you prefer to refer to my rings in fractional inches or millimeters instead of the letters, it's no problem. Use whatever system you feel most comfortable with.

Spider's customers: If you are used to Spider's old numbering system, please note that it does not correspond exactly to mine. Letters D through H are the same, but the others are different. To order from her, use the 64th inch increment, followed by the wire gauge. So D20 would be 8:20, where 20 is the gauge and 8 refers to 8/64 inch inner diameter (in other words, a 20g 8/64 ring, generally reduced to 20g 1/8).


This chart only goes to 3/8", but you can view a complete
Inner Diameter Conversion Chart (PDF)
with IDs in 64" increments, from 1/64" to 1" and their metric equivalents

If you are having trouble opening the file:

download the latest version of
Adobe® Reader®
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My Name Mandrel Size
1/64 insanity 0.016 0.4
2/64 1/32 0.031 0.8
3/64 0.047 1.2
AAA 4/64 1/16 0.063 1.6
A 5/64 0.078 2.0
B 6/64 3/32 0.094 2.4
C 7/64 0.109 2.8
D 8/64 1/8 0.125 3.2
E 9/64 0.141 3.6
F 10/64 5/32 0.156 4.0
G 11/64 0.172 4.4
H 12/64 3/16 0.188 4.8
I 13/64 0.203 5.2
J 14/64 7/32 0.219 5.6
K 15/64 0.234 6.0
L 16/64 1/4 0.250 6.4
M 17/64 0.266 6.7
N 18/64 9/32 0.281 7.1
O 19/64 0.297 7.5
P 20/64 5/16 0.313 7.9
Q 21/64 0.328 8.3
R 22/64 11/32 0.344 8.7
S 23/64 0.359 9.1
T 24/64 3/8 0.375 9.5

Wire Gauges
24 0.02"
0.5 mm
22 0.025"
0.6 mm
21 0.029"
0.724 mm
20 0.032"
0.8 mm
0.8 mm
19 0.036"
0.912 mm
18 0.04"
1.024 mm
1.2 mm
17 0.045"
1.15 mm
16 0.051"
1.291 mm
1.6 mm
14 0.064"
1.63 mm
2.0 mm
The gauge refers to how thick the wire is. Different numbering systems are used, depending on the type of metal. Overall, though, as the gauge number decreases, the thickness of the wire increases. (In other words, in the same metal: 24g is always thinner than 22g, which in turn, is thinner than 20g.).

The table at the left shows the wire diameter of the rings I sell in Sterling Silver vs Base Metal (Aluminum, Brass, Bronze, Copper and Stainless Steel).

Important:If you purchase rings from a different supplier, make sure to check their wire diameters, as they may be different from the ones I sell.

Many serious maillers prefer to use wire measurements instead of gauges so that others know exactly what the wire size is. When calculating the Aspect Ratio of your rings, you must convert the wire gauge to either mm or inches to match the units of the rings ID. Your results won't be accurate if you try to plug wire gauges into the AR formula!

Comparing Rings of Different Metals

If you'd like to move from base metal to sterling rings, the chart below shows which of my rings most closely correspond with one another. These are only rough estimations! The rings do not match up perfectly; a weave that is tight with base metal rings might be impossibly tight with sterling rings, and vice-versa. (There are also slight differences between base metal rings of the same size. In particular, copper, with its minimal springback, tends to create tighter weaves than other metals in the same size.) This chart is only meant as a general guide. If you have questions about the feasibility of a specific weave, let me know before purchasing rings. (Before contacting me, make sure to check out the Stats and Uses charts in the supplies section.)

Remember that the chart below is for my rings only; you should always speak directly with your other suppliers regarding ring sizes, as their rings may be different.

Base Metal

D20 D20

F20 F20 or F19

F18 F17

H18 H17

L18 L16

N16 n/a
(O14 is close, but
slightly bigger)

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