How to Measure Ring Size

For precise sizing, we recommend a ring mandrel—a tapered rod marked with sizes—to measure an existing ring worn on the same finger. Alternatively, a finger-sizing tool, typically a set of graduated rings, can be used directly on the finger to determine the ideal size.

18 KARATS Diamond Ring

Make Your Own Ring Sizer

For the most accurate results, we recommend professional sizing whenever possible—but this method offers a helpful starting point from the comfort of home.

  1. Cut a piece of string, floss, thin paper, or yarn at least 3 inches in length.
  2. Gently wrap it around the base of your finger for a comfortable yet snug fit.
  3. Mark where the end of the string overlaps.
  4. Lay the string flat and measure from the end to your mark using a rule.
SHOP RING SIZERS

How Should a Ring Fit?

A well-sized ring should glide effortlessly over the knuckle with gentle resistance and rest securely on the finger with a comfortable snugness. It should never feel tight or require force to remove.

Ring Size Chart

18 KARATS uses universally recognized US sizes for our rings and wedding bands. The chart below matches US sizes with inside finger circumference and equivalents in international sizing. For quarter-size increments, we recommend using the UK sizing option through our Ring Builder. For any questions about sizing, contact us—we’re here to help!

CONTACT US
Inside CUS, CA, MXUK, SA, AUFRAS, DE, RU IT, NL, ES, CH
INMM
1.7444.23F44144
1.7744.83.25F 1/24514 1/44 5/8
1.7945.53.5G45.514 1/25 1/4
1.8246.13.75G 1/24614 3/45 7/8
1.8446.84H47156 1/2
1.8747.44.25H 1/247.5---7 1/8
1.89484.5I4815 1/47 3/4
1.9248.74.75J48.515 1/28 3/8
1.9449.35J 1/24915 3/49
1.97505.25K50169 5/8
1.9950.65.5K 1/250.516 1/410 1/4
2.0251.25.75L51---10 7/8
2.0451.96L 1/25216 1/211 1/2
2.0752.56.25M52.516 3/412 1/8
2.0953.16.5M 1/2531712 3/4
2.1253.86.75N54---13 3/8
2.1454.47N 1/254.517 1/414
2.1755.17.25O5517 1/214 5/8
2.1955.77.5O 1/25617 3/415 1/4
2.2256.37.75P56.51815 7/8
2.24578P 1/257---16 1/2
2.2757.68.25Q5818 1/417 1/8
2.2958.38.5Q 1/258.518 1/217 3/4
2.3258.98.75R5918 3/418 3/8
2.3459.59R 1/2601919
2.3760.29.25S60.519 1/419 5/8
2.3960.89.5S 1/26119 1/220 1/4
2.4261.49.75T61.5---20 7/8
2.4462.110T 1/26219 3/421 1/2
2.4762.710.25U632022 1/8
2.4963.410.5U 1/263.5---22 3/4
2.526410.75V6420 1/223 3/8
2.5464.611V 1/26520 3/424
2.5765.311.25W65.5---24 5/8
2.5965.911.5W 1/2662125 1/4
2.6266.611.75X6721 1/425 7/8
2.6567.212X 1/267.521 1/226 1/2
2.6868.112.25Y68---27 1/8
2.7168.512.5Z6921 3/427 3/4
2.7269.112.75Z 1/269.5---28 3/8
2.7569.713---702229