Chain gauge to mm converter
Enter your chain’s gauge number to see its typical width in millimetres.
Chain gauge converter
Enter a gauge number to see its width in millimetres.
Typical finished width across published supplier listings, rounded to 0.1 mm. Your chain can differ, so measure it if the fit matters.
Chain gauge to mm chart
Typical finished width for each gauge, with the range across the suppliers we compared. Rows backed by one source say so.
Curbgauge 035 to 400
Curb links that lie flat: plain, diamond-cut, bevelled and pavé (flat diamond-cut) curb. Miami Cuban, square and double-diamond-cut curb run narrower or wider at the same number and are not included.
| Gauge | Typical width | Range and sources |
|---|---|---|
| 035 | 1.0 mm | 1.0 mm1 source: Alfred & Vincent |
| 040 | 1.4 mm | 1.3–1.5 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 050 | 1.8 mm | 1.7–1.8 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 060 | 2.1 mm | 2.0–2.2 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 080 | 3.0 mm | 2.8–3.0 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 100 | 3.7 mm | 3.6–3.7 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 120 | 4.5 mm | 4.3–4.6 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
| 150 | 5.5 mm | 5.3–6.0 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
| 180 | 7.0 mm | 6.2–7.0 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
| 200 | 7.5 mm | 6.9–7.5 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
| 220 | 8.2 mm | 8.0–8.3 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 250 | 9.0 mm | 8.9–10.6 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
| 300 | 11.0 mm | 10.5–12.3 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
| 350 | 13.0 mm | 12.3–14.0 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
| 400 | 14.0 mm | 13.5–14.5 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
Figarogauge 040 to 400
Figaro in 1+1 and 1+3 patterns, including bevelled and pavé flat figaro. Oval figaro runs wider and is not included.
| Gauge | Typical width | Range and sources |
|---|---|---|
| 040 | 1.4 mm | 1.4 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 050 | 1.9 mm | 1.8–1.9 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 060 | 2.2 mm | 2.1–2.3 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 080 | 3.0 mm | 2.8–3.0 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 100 | 3.6 mm | 3.3–3.8 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 120 | 4.5 mm | 4.2–5.0 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
| 150 | 5.5 mm | 5.3–5.5 mm3 sources: Alfred & Vincent, Australian wholesaler, Lumare Gioia |
| 180 | 6.4 mm | 6.0–7.0 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 200 | 7.4 mm | 7.3–7.5 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 220 | 7.9 mm | 7.5–8.0 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 250 | 9.3 mm | 9.0–9.5 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 300 | 10.9 mm | 10.8–11.0 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 350 | 13.3 mm | 13.0–13.5 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 400 | 14.5 mm | 14.0–15.0 mm2 sources: Alfred & Vincent, Lumare Gioia |
Ropegauge 030 to 120
Diamond-cut Italian rope. Heavier solid rope runs wider at the same number and is not included.
| Gauge | Typical width | Range and sources |
|---|---|---|
| 030 | 1.4 mm | 1.4 mm1 source: Alfred & Vincent |
| 035 | 1.7 mm | 1.6–1.7 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 040 | 1.9 mm | 1.8–2.0 mm2 sources: Alfred & Vincent, Banter |
| 050 | 2.3 mm | 2.0–2.5 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 060 | 2.5 mm | 2.5 mm1 source: Alfred & Vincent |
| 070 | 3.1 mm | 3.0–3.2 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 080 | 3.6 mm | 3.5–3.8 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 100 | 4.6 mm | 4.5–4.8 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 120 | 5.4 mm | 5.0–5.8 mm2 sources: Alfred & Vincent, Lumare Gioia |
Box (Venetian)gauge 010 to 065
Square Venetian box chain. Rounded and eight-sided box are not included.
| Gauge | Typical width | Range and sources |
|---|---|---|
| 010 | 0.7 mm | 0.7 mm1 source: Alfred & Vincent |
| 015 | 0.8 mm | 0.8 mm1 source: Alfred & Vincent |
| 019 | 1.0 mm | 1.0 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 022 | 1.2 mm | 1.1–1.2 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 024 | 1.3 mm | 1.3 mm1 source: Alfred & Vincent |
| 028 | 1.4 mm | 1.4 mm1 source: Alfred & Vincent |
| 036 | 1.8 mm | 1.8 mm1 source: Alfred & Vincent |
| 050 | 2.5 mm | 2.5 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 057 | 3.0 mm | 3.0 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 065 | 3.9 mm | 3.8–4.0 mm2 sources: Alfred & Vincent, Lumare Gioia |
Snake (round)gauge 010 to 050
Round snake chain. Square (four-sided) and flexible snake are numbered differently and are not included.
| Gauge | Typical width | Range and sources |
|---|---|---|
| 010 | 0.7 mm | 0.7 mm1 source: Alfred & Vincent |
| 015 | 0.8 mm | 0.8 mm1 source: Alfred & Vincent |
| 020 | 0.9 mm | 0.8–0.9 mm2 sources: Alfred & Vincent, Silver Palace |
| 025 | 1.1 mm | 1.0–1.1 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 030 | 1.2 mm | 1.2 mm1 source: Alfred & Vincent |
| 035 | 1.4 mm | 1.4 mm1 source: Alfred & Vincent |
| 040 | 1.6 mm | 1.6 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 050 | 1.9 mm | 1.9 mm1 source: Alfred & Vincent |
Trace (cable)gauge 040 to 150
Trace or cable chain with links at right angles, plain or diamond-cut, including bevelled anchor and open cable. Belcher (rolo) chain is sold by link size instead.
| Gauge | Typical width | Range and sources |
|---|---|---|
| 040 | 1.6 mm | 1.4–1.7 mm2 sources: Australian wholesaler, Palloys |
| 050 | 1.8 mm | 1.6–2.1 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 080 | 3.1 mm | 2.7–3.2 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 100 | 3.8 mm | 3.8 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 120 | 4.5 mm | 4.5 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 150 | 5.7 mm | 5.2–6.0 mm2 sources: Alfred & Vincent, Lumare Gioia |
Wheat (spiga)gauge 030 to 180
Wheat or spiga chain, round or diamond-cut.
| Gauge | Typical width | Range and sources |
|---|---|---|
| 030 | 1.3 mm | 1.2–1.3 mm2 sources: Alfred & Vincent, Australian wholesaler |
| 100 | 3.9 mm | 3.5–4.2 mm2 sources: Alfred & Vincent, Lumare Gioia |
| 180 | 6.0 mm | 6.0 mm1 source: Alfred & Vincent |
How it works & reference guideMeasuring tips, examples and the details behind this tool
Gauge is a size code, not a measurement
Italian-made chain is sold by a three-digit gauge number, such as 030, 050 or 100. The number grows with the chain, but it is not a width in millimetres and it is not a wire gauge. Each chain style turns the same number into a different width, because its links are shaped differently. Gauge 050 is about 1.8 mm in curb but about 2.3 mm in rope.
Wire gauges run the other way, where a higher number means thinner wire. For example, Halstead describes its 1 mm Italian curb chain as 29-gauge (0.27 mm) wire.
Makers also finish links differently. Diamond-cutting, bevelling and flattening change the finished width, so two chains with the same gauge and style can differ by a few tenths of a millimetre.
Measuring a chain you own
Lay it flat without stretching it. Measure across the outside of a link with callipers, away from the clasp, and check a few links. A photo or a screen cannot give an accurate measurement.
Where the figures come from
We compared chain widths published by Australian and overseas suppliers, checked on 2 October 2026. A width is listed only when two sources give it, or when one source names the number as a gauge. The typical width is the middle value across sources, with each source counted once. The range shows every figure we found, rounded to 0.1 mm. We never estimate a gauge that no source lists.
- Alfred & Vincent (United States, checked 2 October 2026). Online retailer of Italian sterling silver chain. Each listing gives the width with its gauge, such as “1.8mm (Gauge 050)”.
- Lumare Gioia Italian chain (via Robinsons Jewelers) (United States, checked 2 October 2026). Italian sterling chain sold under the Lumare Gioia name, read from Robinsons Jewelers’ listings. The three-digit block in each catalogue number roughly follows the gauge series (within about 15%); a QCB120 curb is listed at 4.5 mm. Used only alongside another source.
- Australian trade chain wholesaler (Australia, checked 9 September 2026). Trade catalogue for 9ct and 18ct gold, platinum and sterling silver chain. Product codes carry the gauge, and gold and silver versions are listed separately.
- Palloys (Australia, checked 9 September 2026). Australian precious metals supplier. Its CA40 trace chain is listed at 1.6 mm.
- Banter by Piercing Pagoda (United States, checked 2 October 2026). Jewellery retailer. Lists its Italian diamond-cut rope as “040 Gauge”, 2 mm wide.
- Silver Palace (United States, checked 2 October 2026). Sterling silver wholesaler. Lists “Snake Round DC 020” chain at 0.8 mm.
Not charted: belcher (rolo) and paperclip chains, which are sold by link size, and franco, byzantine, herringbone and Singapore chains, whose numbers differ between makers. Miami Cuban, square curb, oval figaro and square snake are left out of their style rows because they run wider or narrower at the same number.
Common questions
How do I convert chain gauge to millimetres?
Look up the gauge number for your chain’s style. A gauge is a size code, not a measurement, so the same number gives a different width in each style: gauge 050 is about 1.8 mm in curb, about 2.3 mm in rope and about 2.5 mm in box chain. There is no single formula that works across styles.How wide is a 100 gauge chain?
It depends on the style. Across the published listings we compared, a 100 gauge chain is about 3.7 mm in curb, about 3.6 mm in figaro, about 4.6 mm in rope and about 3.8 mm in trace. Choose the style in the converter to see the range and sources.Is chain gauge the same as wire gauge?
No. Italian chain gauge numbers grow with the chain, so a 100 is wider than a 050. American and British wire gauges run the other way, where a higher number means thinner wire. For example, Halstead describes its 1 mm Italian curb chain as 29-gauge (0.27 mm) wire.Why do suppliers list different widths for the same gauge?
Makers cut, bevel and flatten links differently, and gold and silver versions of one chain can be listed at different widths. One Australian trade catalogue lists its 100 gauge figaro at 3.3 mm in gold and 3.8 mm in silver. That is why we show a typical width and a range: a 150 gauge curb runs 5.3–6.0 mm across our sources.What if my chain style is not listed?
Belcher (rolo) and paperclip chains are usually sold by link size rather than gauge, and makers number franco, byzantine, herringbone and Singapore chains differently from one another. Measure across the chain instead, or ask our jewellers to check it.Will a chain fit through my pendant?
Chain width alone cannot confirm pendant fit. The end fitting, clasp and pendant bail opening also need to fit, and the chain must suit the pendant. Ask a jeweller to check the actual chain and pendant together.
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