Useful Tips For When Sizing Your Ring

Time Of Day

An ideal time to measure your finger size is in the evening. Most people’s fingers tend to be at their largest in the evening and smaller in the morning. Measuring your finger size in the evening will guarantee a comfortable fit. 

Optimal Temperature

Fingers tend to react to temperatures, and can change size depending on the weather. The cold winter air will shrink fingers while the opposite happens in summer or when it’s warm and humid. Avoid measuring finger size outside in the very cold or very hot. 

Fingers Expand And Contract

Other factors can cause fingers to grow such as exercising, water retention, pregnancy, ageing, and arthritis. Weight loss and low temperatures can cause fingers to decrease in size. 

Thicker Bands

Thicker ring bands (larger than 6mm) will fit tighter. It is advised to always go for half a size up when purchasing a thicker band, for the ring to be comfortable. 

Please note that the information in the guide is provided for guidance only and Rithm is not responsible for any errors that occur as a result of using this guide.
Inside Diameter  Inside Circumference Sizes
MM Inches MM Inches British & Australian  US & Canada French & Russian German Japanese Swiss
9.91 0.390 31.13 1.22 - 0000 - - - -
10.72 0.442 33.68 1.39 - 00 - - - -
11.53 0.454 36.22 1.43 - 0 - - - -
11.95 0.474 37.54 1.49 A 1/2 - - - -
12.18 0.482 38.26 1.51 A 1/2 3/4 - - - -
12.37 0.487 38.86 1.53 B 1 - - 1 -
12.60 0.496 39.58 1.56 B 1/2 1 1/4 - - - -
12.78 0.503 40.15 1.58 C 1 1/2 - - - -
13.00 0.512 40.84 1.61 C 1/2 1 3/4 - - - -
13.21 0.520 41.50 1.63 D 2 41 1/2 13 1/2 2 1 1/2
13.41 0.528 42.13 1.66 D 1/2 2 1/4 - - - -
13.61 0.536 42.76 1.68 E 2 1/2 42 3/4 13 3/4 3 2 3/4
13.83 0.544 43.45 1.71 E 1/2 2 3/4 - - - -
14.05 0.553 44.14 1.74 F 3 44 14 4 4
14.15 0.557 44.45 1.75 F 1/2 3 1/8 - - - -
14.25 0.561 44.77 1.76 F 3/4 3 1/4 - - - -
14.36 0.565 45.11 1.77 G 3 3/8 45 1/4 - 5 5 1/4
14.45 0.569 45.40 1.79 G 1/4 3 1/2 - 14 1/2 - -
14.56 0.573 45.74 1.80 G 1/2 3 5/8 - - 6 -
14.65 0.577 46.02 1.81 H 3 3/4 46 1/2 - - 6 1/2
14.86 0.585 46.68 1.84 H 1/2 4 - 15 7 -
15.04 0.592 47.25 1.86 I 4 1/4 47 3/4 - - 7 3/4
15.27 0.601 47.97 1.89 I 1/2 4 1/2 - 15 1/4 8 -
15.40 0.606 48.38 1.90 J 4 5/8 49 15 1/2 - 9
15.53 0.611 48.79 1.92 J 1/4 4 3/4 - - - -
15.70 0.618 49.32 1.94 J 1/2 5 - 15 3/4 9 -
15.80 0.622 49.64 1.95 K 5 1/8 50 - - 10
15.90 0.626 49.95 1.97 K 1/4 5 1/4 - - - -
16.00 0.630 50.27 1.98 K 1/2 5 3/8 - - 10 -
16.10 0.634 50.58 1.99 L 5 1/2 51 3/4 16 - 11 3/4
16.30 0.642 51.21 2.02 L 1/4 5 3/4 - - - -
16.41 0.646 51.55 2.03 L 1/2 5 7/8 - - - -
16.51 0.650 51.87 2.04 M 6 52 3/4 16 1/2 12 12 3/4
16.71 0.658 52.50 2.07 M 1/2 6 1/4 - - - -
16.92 0.666 53.16 2.09 N 6 1/2 54 17 13 14
17.13 0.674 53.82 2.12 N 1/2 6 3/4 - - - -
17.35 0.683 54.51 2.15 O 7 55 1/4 17 1/4 14 15 1/4
17.45 0.687 54.82 2.16 O 1/2 7 1/4 - - - -
17.75 0.699 55.76 2.20 P 7 1/2 56 1/2 17 3/4 15 16 1/2
17.97 0.707 56.45 2.22 P 1/2 7 3/4 - - - -
18.19 0.716 57.15 2.25 Q 8 57 3/4 18 16 17 3/4
18.35 0.722 57.65 2.27 Q 1/2 8 1/4 - - - -
18.53 0.729 58.21 2.29 Q 3/4 8 1/2 - 18 1/2 17 -
18.61 0.733 58.47 2.30 R 8 5/8 59 - - 19
18.69 0.736 58.72 2.31 R 1/4 8 3/4 - - - -
18.80 0.740 59.06 2.32 R 1/2 8 7/8 - - - -
18.89 0.748 59.34 2.35 R 3/4 9 - 19 18 -
19.10 0.752 60.00 2.36 S 9 1/8 60 1/4 - - 20 1/4
19.22 0.757 60.38 2.38 S 1/4 9 1/4 - - - -
19.31 0.760 60.66 2.39 S 1/2 9 3/8 - - - -
19.41 0.764 60.98 2.40 S 3/4 9 1/2 - 19 1/2 19 -
19.51 0.768 61.29 2.41 T 9 5/8 61 1/2 - - 21 1/2
19.62 0.772 61.64 2.43 T 1/4 9 3/4 - - - -
19.84 0.781 62.33 2.45 T 1/2 10 - 20 20 -
20.02 0.788 62.89 2.48 U 10 1/4 62 3/4 - 21 22 3/4
20.20 0.797 63.46 2.50 U 1/2 10 1/2 - 20 1/4 22 -
20.32 0.800 63.84 2.51 V 10 5/8 63 - - 23 3/4
20.44 0.805 64.21 2.53 V 1/4 10 3/4 - - - -
20.68 0.814 64.97 2.56 V 1/2 11 - 20 3/4 23 -
20.76 0.817 65.22 2.57 W 11 1/8 65 - - 25
20.85 0.821 65.50 2.58 W 1/4 11 1/4 - - - -
20.94 0.824 65.78 2.59 W 1/2 11 3/8 - - - -
21.08 0.830 66.22 2.61 W 3/4 11 1/2 - 21 24 -
21.18 0.834 66.54 2.62 X 11 5/8 66 1/4 - - 26 1/4
21.24 0.836 66.73 2.63 X 1/4 11 3/4 - - - -
21.30 0.839 66.92 2.64 X 1/2 11 7/8 - - - -
21.49 0.846 67.51 2.66 Y 12 67 1/2 21 1/4 25 27 1/2
21.69 0.854 68.14 2.68 Y 1/2 12 1/4 - - - -
21.89 0.862 68.77 2.71 Z 12 1/2 68 3/4 21 3/4 26 28 3/4
22.10 0.870 69.43 2.73 Z +1/2 12 3/4 - - - -
22.33 0.879 70.15 2.76 Z+1 13 - 22 27 -
22.60 0.890 71.00 2.80 Z+1.5 13.5 - - - -
22.69 0.893 71.28 2.81 Z+2 - - - - -
22.92 0.902 72.00 2.83 Z+2.5 - - - - -
23.06 0.908 72.45 2.85 Z+3 - - - - -
23.24 0.915 73.01 2.87 Z+3.5 - - - - -
23.47 0.924 73.73 2.90 Z+4 - - - - -
23.55 0.927 73.98 2.91 Z+4.5 - - - - -
23.87 0.940 74.99 2.95 Z+5 - - - - -
24.27 0.956 76.25 3.00 Z+6 - - - - -