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Ring Size Conversion Chart
International Ring Sizes

All 25karats rings are manufactured in US standard ring size. Ring sizes vary by country. If you already know your ring size and just need to convert it to another scale, see our international ring size conversion chart below.

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International Ring Size Conversion Chart
Inside Diameter Inches
Inside Diameter mm
Inside Circumference Inches
Inside Circumference mm
🇺🇸 🇨🇦 USA & Canada
🇬🇧 🇮🇪 🇦🇺 🇳🇿 UK & Commonwealth
🇪🇺 European
0.458 11.6 1.438 36.5 — — —
0.466 11.8 1.463 37.2 — — —
0.474 12 1.488 37.8 — A —
0.482 12.2 1.513 38.4 — A ½ —
0.49 12.4 1.539 39.1 1 B —
0.498 12.6 1.564 39.7 1¼ B½ —
0.506 12.9 1.589 40.4 1½ C —
0.514 13.1 1.614 41 1¾ C½ —
0.522 13.3 1.639 41.6 2 D 1.5
0.53 13.5 1.664 42.3 2¼ D½ —
0.538 13.7 1.689 42.9 2½ E 2.75
0.546 13.9 1.714 43.5 2¾ E½ —
0.554 14.1 1.74 44.2 3 F 4
0.562 14.3 1.765 44.8 3¼ F½ 5.25
0.57 14.5 1.79 45.5 3½ G —
0.578 14.7 1.815 46.1 3¾ G½ 6.5
0.586 14.9 1.84 46.7 4 H —
0.594 15.1 1.865 47.4 4¼ H½ 7.75
0.602 15.3 1.89 48 4½ I —
0.61 15.5 1.915 48.7 4¾ J 9
0.618 15.7 1.941 49.3 5 J½ —
0.626 15.9 1.966 49.9 5¼ K 10
0.634 16.1 1.991 50.6 5½ K½ —
0.642 16.3 2.016 51.2 5¾ L 11.75
0.65 16.5 2.041 51.8 6 L½ 12.75
0.658 16.7 2.066 52.5 6¼ M 12.75
0.666 16.9 2.091 53.1 6½ M½ 14
0.674 17.1 2.116 53.8 6¾ N —
0.682 17.3 2.141 54.4 7 N½ 15.25
0.69 17.5 2.167 55 7¼ O —
0.698 17.7 2.192 55.7 7½ O½ 16.5
0.706 17.9 2.217 56.3 7¾ P —
0.714 18.1 2.242 56.9 8 P½ 17.75
0.722 18.3 2.267 57.6 8¼ Q —
0.73 18.5 2.292 58.2 8½ Q½ —
0.738 18.7 2.317 58.9 8¾ R 19
0.746 18.9 2.342 59.5 9 R½ —
0.754 19.2 2.368 60.1 9¼ S 20.25
0.762 19.4 2.393 60.8 9½ S½ —
0.77 19.6 2.418 61.4 9¾ T 21.5
0.778 19.8 2.443 62.1 10 T½ —
0.786 20 2.468 62.7 10¼ U —
0.794 20.2 2.493 63.3 10½ U½ 22.75
0.802 20.4 2.518 64 10¾ V —
0.81 20.6 2.543 64.6 11 V½ —
0.818 20.8 2.569 65.2 11¼ W 25
0.826 21 2.594 65.9 11½ W½ —
0.834 21.2 2.619 66.5 11¾ X —
0.842 21.4 2.644 67.2 12 X½ 27.5
0.85 21.6 2.669 67.8 12¼ Y —
0.858 21.8 2.694 68.4 12½ Z 28.75
0.866 22 2.719 69.1 12¾ Z½ —
0.874 22.2 2.744 69.7 13 Z1 —
0.882 22.4 2.769 70.3 13¼ Z1 —
0.89 22.6 2.795 71 13½ — —
0.898 22.8 2.82 71.6 13¾ Z2 —
0.906 23 2.845 72.3 14 Z3 —
0.914 23.2 2.87 72.9 14¼ — —
0.922 23.4 2.895 73.5 14½ Z4 —
0.93 23.6 2.92 74.2 14¾ — —
0.938 23.8 2.945 74.8 15 — —
0.946 24 2.97 75.4 15¼ — —
0.954 24.2 2.996 76.1 15½ — —
0.962 24.4 3.021 76.7 15¾ — —
0.97 24.6 3.046 77.4 16 — —
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Free 60-Day Resizing & Exchanges

At 25karats, we offer free 60-day resizing and exchanges to ensure a perfect fit. Most designs can be resized up to one size bigger or smaller or exchanged for a new size within 60 days at no cost.

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