How to Know Your True Ring Size — According to Jewelry Experts

The size of a finger is measured in millimeters (half sizes are separated by 0.4 mm and full sizes by 0.8 mm) to be as precise as possible. "Most fashion jewelry comes in whole and half sizes only, but in fine jewelry, we can get as fine as quarter sizes (6.75, 8.25, etc.), ensuring you have a really accurate fit," Brynne Overton, digital coordinator of Valerie Madison, told POPSUGAR. That means even the slightest fraction of size can affect the accuracy of the fit.

A ring that fits well will comfortably glide over your knuckles and be slightly tight around your finger. According to Jogia, there should be some friction putting the ring on and taking it off. If it easily comes off by moving your fingers, it's too loose. A representative at Mociun believes the ring should not spin around your finger: "a good fit will ensure a stone doesn't slide to the side or back of your finger."

Yoon suggests avoiding what she calls a muffin top. "You want to avoid the ring pinching you in any way, causing a muffin top: where the ring is a little too snug so that it looks uncomfortable." Overton said rings should not cause pain or require water or soap to remove. "A really great test for this is that another person should not be able to remove your ring from your finger with ease."

If you notice you have a more pronounced knuckle in the middle of your finger, make sure you communicate that with the jeweler when sharing your ring size. Chances are the jeweler will go up or down by a quarter size, creating a better fit for you. Overton also reminded us: "A wider band size means more metal, which will affect how the ring fits. Any band that's roughly 4 mm and up might need to be sized up by a half to full size to accommodate movement and the extra metal on your finger."

Rings can be adjusted, to a point. "In order to resize a ring, you have to cut the band and either stretch or fold the ring to accommodate the size change," Overton said. "If you have an infinity band with diamonds all the way around, it's particularly tricky [because] folding the ring can loosen the settings, and stretching can end up crunching the stones a little bit."

In Jogia's experience, most engagement rings can safely be sized up or down two sizes and should never need more alteration than that or the structural integrity of the ring will be affected. "Stones could become loose and potentially fall out. In many cases, you will not end up with a perfectly round ring," he said. If you anticipate needing to resize and you want diamonds on the band of your ring, you may want to opt for a setting with diamonds set just three quarters of the way around. Generally speaking, it's easier to size down than up.