Printable Ring Sizer and US Ring Size Chart
Short answer: print this page at 100% scale, check that the black bar below is exactly 50 mm, then wrap the paper strip around your finger or lay a ring that fits on the circles. Match the millimeters to the chart to get your US ring size.
1. Check the print scale
This bar must measure 50 mm (about 1.97 in). If it does not, turn off "fit to page" and print at 100%.
2. Paper strip sizer
Cut along the dashed line. Wrap the strip around the base of your finger, snug but able to slide over the knuckle, and read the number where the end overlaps. That number is your inside circumference in millimeters.
3. Ring circles (true size)
Lay a ring that already fits the same finger on the circles. Choose the circle whose line sits just inside the ring.
4. US ring size chart in mm and inches
| US size | Inside diameter (mm) | Inside circumference (mm) | Diameter (in) |
|---|---|---|---|
| 3 | 14.1 | 44.2 | 0.554 |
| 3.5 | 14.5 | 45.5 | 0.570 |
| 4 | 14.9 | 46.8 | 0.586 |
| 4.5 | 15.3 | 48.0 | 0.602 |
| 5 | 15.7 | 49.3 | 0.618 |
| 5.5 | 16.1 | 50.6 | 0.634 |
| 6 | 16.5 | 51.9 | 0.650 |
| 6.5 | 16.9 | 53.1 | 0.666 |
| 7 | 17.3 | 54.4 | 0.682 |
| 7.5 | 17.7 | 55.7 | 0.698 |
| 8 | 18.1 | 57.0 | 0.714 |
| 8.5 | 18.5 | 58.2 | 0.730 |
| 9 | 18.9 | 59.5 | 0.746 |
| 9.5 | 19.4 | 60.8 | 0.762 |
| 10 | 19.8 | 62.1 | 0.778 |
| 10.5 | 20.2 | 63.3 | 0.794 |
| 11 | 20.6 | 64.6 | 0.810 |
| 11.5 | 21.0 | 65.9 | 0.826 |
| 12 | 21.4 | 67.2 | 0.842 |
| 12.5 | 21.8 | 68.5 | 0.858 |
| 13 | 22.2 | 69.7 | 0.874 |
Values follow the US and Canada standard (inside diameter in mm = 11.63 + 0.8128 x size). Measure at the end of the day, when fingers are slightly larger, and size up for a wide signet band.
Questions
How do I make sure the printable ring sizer is the right scale?
Print at 100% or "Actual size" with page scaling turned off, then hold a ruler against the 50 mm check bar. If the bar is not exactly 50 mm long, change the print setting and print again before you measure.
Is a paper strip or an existing ring more accurate?
An existing ring that fits the same finger is more reliable, because paper can stretch or be pulled too tight. Lay the ring on the circles and pick the circle whose line sits just inside the ring.
What if I am between two sizes?
Choose the larger size, especially for a wide signet band or if your knuckles are larger than the base of your finger. Fingers also swell slightly in warm weather and late in the day.
What is a size 7 ring in millimeters?
A US size 7 has an inside diameter of about 17.3 mm and an inside circumference of about 54.4 mm. The table on this page lists every half size from 3 to 13.
Found your size? Every ring is made to order in US sizes, with a design proof before production. Browse the rings or see monogram rings and family crest rings.