An interactive tool to convert your finger measurements (circumference or diameter) into standard ring sizes across the US, UK, and EU.
Finding your correct ring size at home is easier than you might think. The most common method is the 'string or paper' method. Wrap a piece of string or a thin strip of paper around the base of your finger. Mark where the string or paper overlaps to form a complete circle. Then, measure the length from the starting end to the mark with a ruler in millimeters (mm). This measurement is your finger's circumference. Input this value into our interactive ring size calculator, select 'Circumference,' and it will instantly provide your standard US, UK, and EU ring sizes.
If you are buying a ring as a surprise gift, measuring the person's finger directly might ruin the surprise. Instead, find a ring that currently fits them well on the specific finger you are shopping for. Place the ring on a flat ruler and measure the straight distance across the inside of the ring, from edge to edge. This is the 'inner diameter.' Enter this diameter measurement into our calculator to find the exact size.
Ring sizing systems vary significantly around the world, which can make international jewelry shopping confusing. In the United States and Canada, ring sizes are represented by numbers, typically ranging from 3 to 13 for adults, including half and quarter sizes. The United Kingdom and Australia, however, use an alphabetical system starting from A and going up to Z, often adding half sizes (e.g., M 1/2). The European Union and many other countries use the ISO standard, which is simply the inner circumference of the ring in millimeters. Our calculator automatically bridges these gaps by providing all conversions simultaneously.
To ensure a perfect fit, avoid measuring your fingers when they are very cold, as your fingers shrink in colder temperatures. The best time to measure is at the end of the day when your fingers are at their largest. Additionally, remember that a ring must be large enough to slide over your knuckle comfortably. If you have particularly large knuckles, you may need to order a half size up from your base finger measurement.