Everything you need to size wedding bands correctly — including how band width affects fit and the best time to measure.
Wedding rings are worn every day for a lifetime, making correct sizing more important than for almost any other piece of jewellery. Unlike engagement rings — which you often size alone — both partners should be measured professionally for their wedding bands.
This is the most commonly overlooked factor in wedding ring sizing. Wider bands feel tighter than narrow bands of the same size because more surface area contacts the finger. As a rule:
| Band Width | Sizing Adjustment | Notes |
|---|---|---|
| Under 4mm | Normal size | Slim bands — no adjustment needed |
| 4–6mm | Normal or +½ size | Standard ring width — minimal adjustment |
| 6–8mm | +½ size up | Classic men's band width — size up |
| 8–10mm | +1 full size up | Wide bands need a full size increase |
| Over 10mm | +1 to +1.5 sizes up | Very wide bands — always try before buying |
For wedding bands specifically, timing your sizing appointment matters:
Many wedding bands are available in "comfort fit" — a rounded interior profile that slides on and off more easily and feels more comfortable during daily wear. Comfort fit bands typically feel about half a size larger than standard (flat interior) bands of the same nominal size, so you may need to go half a size smaller when choosing comfort fit.
| US / Canada | UK / IRE / AUS | EU | Diameter (mm) | Circumference (mm) | ||
|---|---|---|---|---|---|---|
| 3 | F | 44 | 4 | 4 | 14.1 | 44.2 |
| 3.5 | G | 45 | 5 | 5 | 14.5 | 45.6 |
| 4 | H | 46.5 | 7 | 6.5 | 14.9 | 46.8 |
| 4.5 | I | 48 | 8 | 8 | 15.3 | 48.0 |
| 5 | J | 49 | 9 | 9 | 15.7 | 49.3 |
| 5.5 | K | 50.5 | 11 | 10.5 | 16.1 | 50.6 |
| 6 | L | 51.5 | 12 | 11.5 | 16.5 | 51.9 |
| 6.5 | M | 53 | 13 | 13 | 16.9 | 53.2 |
| 7 | N | 54 | 14 | 14 | 17.3 | 54.4 |
| 7.5 | O | 55.5 | 16 | 15.5 | 17.7 | 55.7 |
| 8 | P | 57 | 17 | 17 | 18.2 | 57.2 |
| 8.5 | Q | 58 | 18 | 18 | 18.5 | 58.2 |
| 9 | R | 59 | 19 | 19 | 18.9 | 59.3 |
| 9.5 | S | 61 | 21 | 21 | 19.4 | 61.0 |
| 10 | T | 62 | 22 | 22 | 19.8 | 62.2 |
| 10.5 | U | 63.5 | 24 | 23.5 | 20.2 | 63.5 |
| 11 | V | 65 | 25 | 25 | 20.7 | 65.0 |
| 11.5 | W | 66 | 26 | 26 | 21.1 | 66.2 |
| 12 | X | 67.5 | 28 | 27.5 | 21.5 | 67.5 |
| 12.5 | Y | 68.5 | 29 | 28.5 | 21.9 | 68.8 |
| 13 | Z | 70 | 30 | 30 | 22.3 | 70.1 |
| 14 | Z+2 | 71 | 31 | 31 | 22.7 | 71.3 |
Many couples have their engagement ring and wedding band custom fitted together. Important considerations: