Printable ring sizer
Print this page, check the square with a ruler, then measure. The check square is the part that matters: browsers shrink pages to fit the paper by default, and a sizer printed 4% small reads about a size and a half too tight. Every printable sizer that skips this step is guessing.
Before you print
- In the print dialog set Scale to100% — not “Fit to page”, not “Shrink to fit”. This is the single step that decides whether the sheet is accurate.
- Use A4 or US Letter. Either works; the gauge fits both.
- Measure the printed square with a ruler. It must be50 mm on every side. If it is not, your printer scaled the page — fix the scale setting and print again rather than trying to correct for it.
Nothing is uploaded and there is no PDF to download — this is the page itself, printed.
1 · Check the scale first
Measure this square. Every side must be exactly 50 mm. If it is not, the sheet is scaled and every size below it will be wrong.
50 mm × 50 mm
A ruler is enough. If you do not have one, a standard bank card is 85.60 mm long and 53.98 mm wide (ISO/IEC 7810) — the square should be a little shorter than the card’s short edge is wide, plus a hair under 4 mm.
2 · Measure a ring you already own
Lay a ring over the circles. The right one is the circle whose outline just disappears inside the ring’s inner edge. If the ring sits between two, take the larger.
- US 314.1 mm · UK F½ · EU 44 · JP 4
- US 414.9 mm · UK H½ · EU 47 · JP 7
- US 515.7 mm · UK J½ · EU 49 · JP 9
- US 616.5 mm · UK L½ · EU 52 · JP 12
- US 717.3 mm · UK N½ · EU 54 · JP 14
- US 818.1 mm · UK P½ · EU 57 · JP 16
- US 918.9 mm · UK R½ · EU 60 · JP 19
- US 1019.8 mm · UK T½ · EU 62 · JP 21
- US 1120.6 mm · UK V½ · EU 65 · JP 24
- US 1221.4 mm · UK Y · EU 67 · JP 26
- US 1322.2 mm · UK Z+1 · EU 70 · JP 29
- US 1423.0 mm · UK Z+3 · EU 72 · JP 31
3 · Or measure your finger
Cut along the strip. Wrap it around the base of your finger, snug but not tight, and read the millimetre mark where the end meets the strip. That figure is your circumference — find it in the table below.
Circumference in millimetres, measured from the left end · cut along the outline · most adult fingers land between 44 and 73 mm
| Circumference | US | UK | EU | JP | Diameter |
|---|---|---|---|---|---|
| 44.2 mm | 3 | F½ | 44 | 4 | 14.1 mm |
| 46.8 mm | 4 | H½ | 47 | 7 | 14.9 mm |
| 49.3 mm | 5 | J½ | 49 | 9 | 15.7 mm |
| 51.9 mm | 6 | L½ | 52 | 12 | 16.5 mm |
| 54.4 mm | 7 | N½ | 54 | 14 | 17.3 mm |
| 57.0 mm | 8 | P½ | 57 | 16 | 18.1 mm |
| 59.5 mm | 9 | R½ | 60 | 19 | 18.9 mm |
| 62.1 mm | 10 | T½ | 62 | 21 | 19.8 mm |
| 64.6 mm | 11 | V½ | 65 | 24 | 20.6 mm |
| 67.2 mm | 12 | Y | 67 | 26 | 21.4 mm |
| 69.7 mm | 13 | Z+1 | 70 | 29 | 22.2 mm |
| 72.3 mm | 14 | Z+3 | 72 | 31 | 23.0 mm |
Published UK letter charts vary by up to half a size, because British scales do not all include the same half letters. Ours follows BS EN 28653 exactly. If your jeweller uses a different chart, give them the circumference in millimetres above instead.
No printer?
The on-screen sizer calibrates against a bank card instead of a printer, which removes the scaling problem entirely, and it carries quarter sizes that paper cannot resolve.
Measure on screen instead →