Ring Size Conversion Chart
Convert between US, UK, EU, and Japanese ring sizes. Select the systems you need, then print or bookmark your custom chart.
Size systems to display
| Diameter (mm) | US | UK | EU | JP |
|---|---|---|---|---|
| 12.37 | 1 | B | 39 | 1 |
| 12.78 | 1.5 | C | 40 | 2 |
| 13.21 | 2 | D | 42 | 3 |
| 13.61 | 2.5 | E | 43 | 4 |
| 14.05 | 3 | F | 44 | 5 |
| 14.45 | 3.5 | G | 45 | 6 |
| 14.86 | 4 | H | 47 | 7 |
| 15.27 | 4.5 | I | 48 | 8 |
| 15.70 | 5 | J | 49 | 9 |
| 16.10 | 5.5 | K | 51 | 10 |
| 16.51 | 6 | L | 52 | 11 |
| 16.92 | 6.5 | M | 53 | 12 |
| 17.35 | 7 | N | 55 | 13 |
| 17.75 | 7.5 | O | 56 | 14 |
| 18.19 | 8 | P | 57 | 15 |
| 18.53 | 8.5 | Q | 58 | 16 |
| 18.89 | 9 | R | 59 | 17 |
| 19.41 | 9.5 | S | 61 | 18 |
| 19.84 | 10 | T | 62 | 19 |
| 20.20 | 10.5 | U | 63 | 20 |
| 20.68 | 11 | V | 65 | 21 |
| 21.08 | 11.5 | W | 66 | 22 |
| 21.49 | 12 | X | 68 | 23 |
| 21.89 | 12.5 | Y | 69 | 24 |
| 22.33 | 13 | Z | 70 | 25 |
| 22.73 | 13.5 | — | 71 | 26 |
| 23.06 | 14 | — | 72 | 27 |
| 23.47 | 14.5 | — | 74 | — |
| 23.87 | 15 | — | 75 | — |
| 24.27 | 15.5 | — | 76 | — |
| 24.64 | 16 | — | 77 | — |
12.37 mm
US: 1UK: BEU: 39JP: 1
12.78 mm
US: 1.5UK: CEU: 40JP: 2
13.21 mm
US: 2UK: DEU: 42JP: 3
13.61 mm
US: 2.5UK: EEU: 43JP: 4
14.05 mm
US: 3UK: FEU: 44JP: 5
14.45 mm
US: 3.5UK: GEU: 45JP: 6
14.86 mm
US: 4UK: HEU: 47JP: 7
15.27 mm
US: 4.5UK: IEU: 48JP: 8
15.70 mm
US: 5UK: JEU: 49JP: 9
16.10 mm
US: 5.5UK: KEU: 51JP: 10
16.51 mm
US: 6UK: LEU: 52JP: 11
16.92 mm
US: 6.5UK: MEU: 53JP: 12
17.35 mm
US: 7UK: NEU: 55JP: 13
17.75 mm
US: 7.5UK: OEU: 56JP: 14
18.19 mm
US: 8UK: PEU: 57JP: 15
18.53 mm
US: 8.5UK: QEU: 58JP: 16
18.89 mm
US: 9UK: REU: 59JP: 17
19.41 mm
US: 9.5UK: SEU: 61JP: 18
19.84 mm
US: 10UK: TEU: 62JP: 19
20.20 mm
US: 10.5UK: UEU: 63JP: 20
20.68 mm
US: 11UK: VEU: 65JP: 21
21.08 mm
US: 11.5UK: WEU: 66JP: 22
21.49 mm
US: 12UK: XEU: 68JP: 23
21.89 mm
US: 12.5UK: YEU: 69JP: 24
22.33 mm
US: 13UK: ZEU: 70JP: 25
22.73 mm
US: 13.5EU: 71JP: 26
23.06 mm
US: 14EU: 72JP: 27
23.47 mm
US: 14.5EU: 74
23.87 mm
US: 15EU: 75
24.27 mm
US: 15.5EU: 76
24.64 mm
US: 16EU: 77
Tips
- To measure your ring size at home, wrap a strip of paper around your finger, mark where it overlaps, and measure the length in mm — that’s your EU size.
- Wide bands (8mm+) need a larger size to slide over the knuckle. Use our ring blank calculator to account for this.
- When in doubt, size up — a ring that’s slightly loose is more comfortable than one that’s stuck.
How it works
Ring sizing systems vary by country, but they all describe the same physical measurement — the inner diameter (or circumference) of the ring. This chart converts between the four most common systems:
- US — arbitrary numbers (1–16 in half sizes), based on a standardized mandrel
- UK — letters A–Z, used in the United Kingdom, Ireland, and Australia
- EU — the inner circumference of the ring in millimeters, rounded to the nearest integer
- JP — numbered system used in Japan (JIS standard)
Because all systems describe the same physical measurement (inner diameter), converting between them is a straightforward lookup — no math required on your part.
Related tools
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