Craft and jewelry wire gauge chart from 10 to 34 AWG with millimetres and the British SWG equal, plus a true-size screen sizer. 20 AWG is 0.812 mm (SWG 21 is 0.813 mm). Finer than 24 AWG, wind 10 turns on a pencil and measure the coil.
01 · 1:1 wire gauge · caliper
THIS IS:
20 AWG COPPER · NOT BUILDING WIRE · 0.81 MM COPPER
The gap is 0.81 mm (0.0320"), which reads as 20 AWG bare solid copper. Measure bare copper for the gauge: insulation is far thicker than the metal.
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Jewelry wire in the US is sold in AWG (Brown & Sharpe); British suppliers often use SWG, which runs slightly thicker at the same number in this range.
| 7/0 | 0.5 | 12.7 | 4/0 AWG |
|---|---|---|---|
| 6/0 | 0.464 | 11.786 | 4/0 AWG |
| 5/0 | 0.432 | 10.973 | 3/0 AWG |
| 4/0 | 0.4 | 10.16 | 3/0 AWG |
| 3/0 | 0.372 | 9.449 | 2/0 AWG |
| 2/0 | 0.348 | 8.839 | 2/0 AWG |
| 0 | 0.324 | 8.23 | 1/0 AWG |
| 1 | 0.3 | 7.62 | 1 AWG |
| 2 | 0.276 | 7.01 | 1 AWG |
| 3 | 0.252 | 6.401 | 2 AWG |
| 4 | 0.232 | 5.893 | 3 AWG |
| 5 | 0.212 | 5.385 | 4 AWG |
| 6 | 0.192 | 4.877 | 4 AWG |
| 7 | 0.176 | 4.47 | 6 AWG |
| 8 | 0.16 | 4.064 | 6 AWG |
| 9 | 0.144 | 3.658 | 8 AWG |
| 10 | 0.128 | 3.251 | 8 AWG |
| 11 | 0.116 | 2.946 | 8 AWG |
| 12 | 0.104 | 2.642 | 10 AWG |
| 13 | 0.092 | 2.337 | 10 AWG |
| 14 | 0.08 | 2.032 | 12 AWG |
| 15 | 0.072 | 1.829 | 14 AWG |
| 16 | 0.064 | 1.626 | 14 AWG |
| 17 | 0.056 | 1.422 | 16 AWG |
| 18 | 0.048 | 1.219 | 16 AWG |
| 19 | 0.04 | 1.016 | 18 AWG |
| 20 | 0.036 | 0.914 | 20 AWG |
| 21 | 0.032 | 0.813 | 20 AWG |
| 22 | 0.028 | 0.711 | 22 AWG |
| 23 | 0.024 | 0.61 | 22 AWG |
| 24 | 0.022 | 0.559 | 24 AWG |
| 25 | 0.02 | 0.508 | 24 AWG |
| 26 | 0.018 | 0.4572 | 26 AWG |
| 27 | 0.0164 | 0.4166 | 26 AWG |
| 28 | 0.0148 | 0.3759 | 26 AWG |
| 29 | 0.0136 | 0.3454 | 28 AWG |
| 30 | 0.0124 | 0.315 | 28 AWG |
| 31 | 0.0116 | 0.2946 | 28 AWG |
| 32 | 0.0108 | 0.2743 | 30 AWG |
| 33 | 0.01 | 0.254 | 30 AWG |
| 34 | 0.0092 | 0.2337 | 30 AWG |
| 35 | 0.0084 | 0.2134 | 32 AWG |
| 36 | 0.0076 | 0.193 | 32 AWG |
| 37 | 0.0068 | 0.1727 | 34 AWG |
| 38 | 0.006 | 0.1524 | 34 AWG |
| 39 | 0.0052 | 0.1321 | 36 AWG |
| 40 | 0.0048 | 0.1219 | 36 AWG |
05 / Field guide
Jewelry and craft wire in the US is sold in AWG, the same Brown & Sharpe scale as electrical wire; British suppliers often use SWG. Between 18 and 28 AWG the sizes differ by a few hundredths of a millimetre, finer than a screen pixel, so the coil method is the reliable way to check one.
Wind 10 tight turns side by side on a pencil or a mandrel, lay the coil between the ruler’s lines and read its length: the wire is that length ÷ 10. 20 AWG is 0.812 mm, so 10 turns measure 8.1 mm; 24 AWG 5.1 mm.
wire diameter = coil length ÷ turns turns per inch = 1 ÷ diameter (in)
SWG runs a little thicker than AWG at the same number in this range (SWG 20 is 0.914 mm, AWG 20 is 0.812 mm). Sheet-metal gauges are a third, unrelated scale; jewelry sheet in the US uses AWG.
A browser does not know how big its pixels are, so the gauge starts from a table of 114 phones, tablets, laptops and monitors matched to your screen’s size and pixel ratio, an estimate good to about five percent. Laying a coin or a bank card on the glass and matching its outline replaces the estimate with a measurement good to a fraction of a percent, saved for this screen only.
Browser zoom is corrected automatically from the pixel ratio; pinch zoom is flagged, because nothing drawn is true size until it is undone.
pixels per mm = CSS px across the card ÷ 85.60 mm ID-1 card: 85.60 × 53.98 mm (ISO/IEC 7810)
Copper, brass, bronze, sterling silver, gold-fill and niobium wire are all sold in AWG. Gauge fixes the diameter, not the stiffness: dead-soft wire bends easily and work-hardens as you shape it, half-hard holds a shape better, and full-hard springs back. Coloured and enamelled craft wire is usually copper with a coating a few hundredths of a millimetre thick, so measure the coil of the coated wire you will use.
As a rule of thumb, 16–18 AWG makes shanks, clasps and structural frames, 20–22 AWG wraps and links, and 24–28 AWG binds beads and fine weaving. 18 AWG is 1.02 mm, 22 AWG 0.644 mm, 26 AWG 0.405 mm.
Questions
20 AWG is 0.0320 inch (0.812 mm). 20 SWG is thicker, 0.036 inch (0.914 mm).
Commonly 18 AWG (1.02 mm) or 16 AWG (1.29 mm) for the shank and 26–28 AWG for wrapping. Softer tempers bend more easily.
Yes. Lower numbers are thicker: 22 AWG is 0.644 mm, 24 AWG 0.511 mm.
Wind 10 tight turns and measure the coil, or use a micrometer. A ruler or a screen cannot resolve a single strand finer than about 0.5 mm.
Temper, not gauge: dead-soft, half-hard and full-hard wire of the same AWG have the same diameter but different stiffness.
Most beading and wire-wrapping work uses 20 to 26 AWG: 20 AWG (0.81 mm) for links and loops, 24–26 AWG for stringing small beads and weaving. Check that the wire passes through the bead holes twice if you plan to loop back.
Yes, in the US both use AWG (Brown & Sharpe). British suppliers may use SWG, which differs at the same number.