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Artem Kononenko/Demand Media

Although, in most cases, you can have a ring re-sized by a jeweler after it has been purchased, it's still a smart idea to know what your ring size is before exchanging money. Knowing your ring size allows you to purchase the jewelry with confidence even if don't have the option of trying it on beforehand. This is especially true when you are purchasing a ring from the Internet. For both, men and women, ring sizes range from a Size 3 to a Size 16. If you want more peace of mind after determining your ring size on your own, verify the size by going to a local jeweler and getting measured. Note that ring sizes are the same for both men and women.

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Artem Kononenko/Demand Media

Cut a piece of string, 5 inches to 6 inches long. It can be any type of string or ribbon, long as it's durable and won't snap.

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Artem Kononenko/Demand Media

Wrap the string around the base of the finger you're measuring. Use your thumb to hold down the base of the string or have someone assist you.

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Artem Kononenko/Demand Media

With either a marker or a pen, mark the spot on the string where it overlaps the end pressed to the base of the finger. The string should have made a full circle. Do not stretch too taught.

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Artem Kononenko/Demand Media

Unwrap the string from your finger and measure the length in millimeters from the base of the string to the point you marked.

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Artem Kononenko/Demand Media

Compare your measurements to a ring chart as given below.

Size 3 corresponds to 44.1 millimeters. Size 3 corresponds to 44.1 millimeters. Size 3.5 corresponds to 45.4 millimeters Size 4 corresponds to 46.7 millimeters Size 4.5 corresponds to 48 millimeters Size 5 corresponds to 49.2 millimeters Size 5.5 corresponds to 50.5 millimeters Size 6 corresponds to 51.8 millimeters Size 6.5 corresponds to 53.1 millimeters Size 7 corresponds to 54.3 millimeters Size 7.5 corresponds to 55.6 millimeters Size 8 corresponds to 56.9 millimeters Size 8.5 corresponds to 58.2 millimeters Size 9 corresponds to 59.4 millimeters Size 9.5 corresponds to 60.7 millimeters Size 10 corresponds to 62 millimeters Size 10.5 corresponds to 63.3 millimeters Size 11 corresponds to 64.5 millimeters Size 11.5 corresponds to 65.8 millimeters Size 12 corresponds to 67.1 millimeters Size 12.5 corresponds to 68.3 millimeters Size 13 corresponds to 69.7 millimeters