Ring Sizing First, figure out what finger you want the ring to go on. Next, measure the circumference of your finger with a string. Use the chart below to determine your ring size. Shop Rings Circumference in MM 49.3 US / CANADA 5 50.6 US / CANADA 5.5 51.9 US / CANADA 6 53.1 US / CANADA 6.554.4 US / CANADA 7 55.7 US / CANADA 7.557 US / CANADA 8 58.3 US / CANADA 8.5 59.5 US / CANADA 9 60.8 US / CANADA 9.562.1 US / CANADA 10 63.4 US / CANADA 10.564.6 US / CANADA 11 65.9 US / CANADA 11.567.2 US / CANADA 12 68.5 US / CANADA 12.569.7 US / CANADA 13