Ring Size Guide: How to Measure at Home Before You Buy

Ring size is one of the few things about online jewelry buying that cannot be fixed after delivery — or can only be fixed with additional cost and effort. Getting it right before you order saves time, money, and the awkward process of returning a ring that did not fit. Here are the three most reliable methods.

Method 1: Use a Ring Sizer

Plastic ring sizers — a set of rings in incrementing sizes — are the most accurate home measurement tool. They are sold as inexpensive accessories on Amazon and in many craft and jewelry supply stores. Try each size on the finger you intend to wear the ring on (ring sizes differ between fingers and between hands). The correct size slides on with light resistance and does not pinch when made into a fist.

Note: ring size varies slightly throughout the day. Fingers are slightly larger in the evening and in warm weather, and slightly smaller in the morning and in cold weather. Measure at the end of the day for a size that accommodates the larger state.

Method 2: Measure an Existing Ring

If the recipient already wears rings on that finger, you can measure an existing ring. Place it on a ruler and measure the inner diameter (the measurement across the inside of the ring, not the outside). A 17mm inner diameter corresponds to a US size 6.5; 18mm to size 8; 19mm to size 9. A complete diameter-to-size conversion chart is available in our ring size reference guide.

This method works well for surprise proposals if you can borrow a ring the person frequently wears on the correct finger. Use a ring they wear on the same hand and the same finger position.

Method 3: Paper Strip Measurement

Cut a thin strip of paper (about 5mm wide) and wrap it snugly around the finger you intend to wear the ring on. Mark where the strip overlaps itself. Measure the length of the strip from the start to the mark in millimeters — this is the circumference. Divide by 3.14 to get the diameter, then use a size chart to convert. This method is less accurate than a ring sizer but adequate for within-half-size accuracy.

When in Doubt, Size Up

If you are between sizes, order the larger size. It is significantly easier and cheaper for a jeweler to size a ring down than up. Sizing down requires removing metal; sizing up requires adding metal, which is more complex and sometimes impossible without affecting the ring design. A ring that is slightly large can also be temporarily sized with a ring guard or sizing beads while you arrange professional resizing.

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