The best ring size to start with is the one that feels comfortable on the finger you’ll actually wear it on. The same finger on the other hand can fit differently. Before ordering online, note the hand and finger, then use one of these two ways to check your size.
Measure a ring you already wear
Choose a ring that fits that finger comfortably and still slides over the knuckle. Lay it flat and use a millimeter ruler or calipers to measure straight across the inside of the opening through the center. Start and finish at the inner metal edges. Write down the inside diameter in millimeters so you can check it against the retailer’s US ring size chart.
Try the measurement twice. If the ring has an oval opening or has bent out of shape, measure your finger with a ring sizer instead. When the new ring will be much wider than the one you measured, ask how the wider band will fit before using the same size.
Use a ring sizer when you’re between sizes
A set of ring sizing loops lets you feel how the size passes over your knuckle and rests at the base of your finger. The loop should slide over with a little resistance and sit comfortably at the base. Try the next size as well if you feel pressure or the loop turns easily on the finger.
If you use a printable guide, set the print scale to 100 percent and check its calibration line with a ruler before measuring. Take a second measurement when your hands are at a normal temperature, especially if the first size felt borderline.
Keep both numbers handy
A US ring size is easier to confirm when you also have the inside diameter in millimeters or the result from a sizing loop. If your measurement falls between sizes, share the measurement and the style you’re considering. The width and inside shape of that particular band can affect the fit.
Once you’ve confirmed the size, look at the band widths and profiles of the styles you like. Explore engagement rings at Starmo Jewelry.