Century Diamonds makes it simple to find the right ring size, but just in case you don’t get the right size the first time around we offer free lifetime ring resizes with any order (Limit 1 per year).
1) Print & Find Your Ring Size – Print this PDF file and find your ring size. If you don’t have access to a printer, let us know and we will mail this to you free of charge.
2) Find her ring size without her knowing! – Trying to find a significant others ring size without them knowing? Read these useful tips in our blog and find them out in no time!
3) International Ring Size Converter – Convert your ring size from other countries to the appropriate US ring size. See the chart below.
If you are still unable to determine your ring size, contact one of our customer service specialists at [email protected]
| U.S. Size | Diameter in Inches | Diameter in MM | Metric MM Equivalent | British | French | German | Japanese | Swiss |
| 0000 | .390 | 9.91 | – | |||||
| 00 | .422 | 10.72 | – | |||||
| 0 | .454 | 11.53 | – | |||||
| 1/2 | .474 | 11.95 | A | |||||
| 3/4 | .482 | 12.18 | A 1/2 | |||||
| 1 | .487 | 12.37 | 38.9 | B | 1 | |||
| 1 1/4 | – | 12.60 | 39.6 | B 1/2 | ||||
| 1 1/2 | .503 | 12.78 | 40.2 | C | ||||
| 1 3/4 | – | 13.00 | 40.8 | C 1/2 | ||||
| 2 | .520 | 13.21 | 41.5 | D | 41 1/2 | 13 1/2 | 2 | 1 1/2 |
| 2 1/4 | – | 13.41 | 42.1 | D 1/2 | – | – | ||
| 2 1/2 | .536 | 13.61 | 42.7 | E | 42 3/4 | 13 3/4 | 3 | 2 3/4 |
| 2 3/4 | – | 13.83 | 43.4 | E 1/2 | – | – | ||
| 3 | .553 | 14.05 | 44.0 | F | 44 | 14 | 4 | 4 |
| 3 1/8 | – | 14.15 | 44.3 | F 1/2 | – | – | ||
| 3 1/4 | – | 14.25 | 44.6 | – | – | – | ||
| 3 3/8 | – | 14.36 | 44.9 | G | 45 1/4 | – | 5 | 5 1/4 |
| 3 1/2 | .569 | 14.45 | 45.2 | – | – | 14 1/2 | ||
| 3 5/8 | – | 14.56 | 45.6 | G 1/2 | – | 6 | ||
| 3 3/4 | – | 14.65 | 45.9 | H | 46 1/2 | 6 1/2 | ||
| 4 | .585 | 14.86 | 46.5 | H 1/2 | – | 15 | 7 | |
| 4 1/4 | – | 15.04 | 47.1 | I | 47 3/4 | 7 3/4 | ||
| 4 1/2 | .601 | 15.27 | 47.8 | I 1/2 | – | 15 1/4 | 8 | |
| 4 5/8 | – | 15.40 | 48.1 | J | 49 | 15 1/2 | 9 | |
| 4 3/4 | – | 15.53 | 48.4 | – | – | |||
| 5 | .618 | 15.70 | 49.0 | J 1/2 | – | 15 3/4 | 9 | |
| 5 1/8 | – | 15.80 | 49.3 | K | 50 | 10 | ||
| 5 1/4 | – | 15.90 | 49.6 | – | – | |||
| 5 3/8 | – | 16.0 | 50.0 | K 1/2 | – | 10 | ||
| 5 1/2 | .634 | 16.10 | 50.3 | L | 51 3/4 | 16 | 11 3/4 | |
| 5 3/4 | – | 16.30 | 50.9 | – | – | |||
| 5 7/8 | – | 16.41 | 51.3 | L 1/2 | – | |||
| 6 | .650 | 16.51 | 51.5 | M | 52 3/4 | 16 1/2 | 12 | 12 3/4 |
| 6 1/4 | – | 16.71 | 52.2 | M 1/2 | – | |||
| 6 1/2 | .666 | 16.92 | 52.8 | N | 54 | 17 | 13 | 14 |
| 6 3/4 | – | 17.13 | 53.4 | N 1/2 | – | |||
| 7 | .683 | 17.35 | 54.0 | O | 55 1/4 | 17 1/4 | 14 | 15 1/4 |
| 7 1/4 | – | 17.45 | 54.7 | O 1/2 | – | |||
| 7 1/2 | .699 | 17.75 | 55.3 | P | 56 1/2 | 17 3/4 | 15 | 16 1/2 |
| 7 3/4 | – | 17.97 | 55.9 | P 1/2 | – | |||
| 8 | .716 | 18.19 | 56.6 | Q | 57 3/4 | 18 | 16 | 17 3/4 |
| 8 1/4 | – | 18.35 | 57.2 | Q 1/2 | – | |||
| 8 1/2 | .732 | 18.53 | 57.8 | – | – | 18 1/2 | 17 | |
| 8 5/8 | – | 18.61 | 58.4 | R | 59 | 19 | ||
| 8 3/4 | – | 18.69 | 58.4 | – | – | |||
| 8 7/8 | – | 18.80 | 59.0 | R 1/2 | – | |||
| 9 | .748 | 18.89 | 59.1 | – | – | 19 | 18 | |
| 9 1/8 | – | 19.10 | 59.4 | S | 60 1/4 | 20 1/4 | ||
| 9 1/4 | – | 19.22 | 59.7 | – | – | |||
| 9 3/8 | – | 19.31 | 60.0 | S 1/2 | – | |||
| 9 1/2 | .764 | 19.41 | 60.3 | – | – | 19 1/2 | 19 | |
| 9 5/8 | – | 19.51 | 60.6 | T | 61 1/2 | 21 1/2 | ||
| 9 3/4 | – | 19.62 | 60.9 | – | – | |||
| 10 | .781 | 19.84 | 61.6 | T 1/2 | – | 20 | 20 | |
| 10 1/4 | – | 20.02 | 62.2 | U | 62 3/4 | 21 | 22 3/4 | |
| 10 1/2 | .797 | 20.20 | 62.8 | U 1/2 | – | 20 1/4 | 22 | |
| 10 5/8 | – | 20.32 | 63.1 | V | 63 | 23 3/4 | ||
| 10 3/4 | – | 20.44 | 63.5 | – | – | |||
| 11 | .814 | 20.68 | 64.1 | V 1/2 | – | 20 3/4 | 23 | |
| 11 1/8 | – | 20.76 | 64.3 | W | 65 | 25 | ||
| 11 1/4 | – | 20.85 | 64.7 | – | – | |||
| 11 3/8 | – | 20.94 | 65.0 | W 1/2 | – | |||
| 11 1/2 | – | 21.08 | 65.3 | – | – | 21 | 24 | |
| 11 5/8 | .830 | 21.18 | 65.7 | X | 66 1/4 | 26 1/4 | ||
| 11 3/4 | – | 21.24 | 66.0 | – | – | |||
| 11 7/8 | – | 21.30 | 66.3 | X 1/2 | – | |||
| 12 | .846 | 21.49 | 66.6 | Y | 67 1/2 | 21 1/4 | 25 | 27 1/2 |
| 12 1/4 | – | 21.69 | 67.2 | Y 1/2 | – | |||
| 12 1/2 | .862 | 21.89 | 67.9 | Z | 68 3/4 | 21 3/4 | 26 | 28 3/4 |
| 12 3/4 | – | 22.10 | 68.5 | Z 1/2 | – |
Use this chart to convert your local standard sizes to your US ring sizes for ordering. Choose your nearest US size. Select the US size that is nearest to yours in the dropdown menus on the product pages. Please contact us if you need assistance.