The most precise British ring size reference โ exact diameter and circumference for every size A to Z+6, 5 measuring methods, printable ruler, and accuracy tips to guarantee a perfect fit
Cut a 1 cm wide strip of paper. Wrap snugly around the base of your finger, mark the overlap, lay flat and measure in mm with a ruler. Best accuracy when done 3 times and averaged.
โ High AccuracyWrap a non-stretchy piece of thread or dental floss around the finger. Mark with a pen where it overlaps, then measure the marked length against a mm ruler.
โ High AccuracyPlace a well-fitting ring on a flat ruler and measure the inner diameter in mm. Match to the Diameter (mm) column in the chart below. Must be from the same finger.
โ High AccuracyPrint the ruler below at 100% scale (no "fit to page"). Cut out a strip and wrap around your finger. Confirm the scale by checking the 10 mm marker with a real ruler before using.
โ ๏ธ Medium AccuracyVisit any UK jeweller (Goldsmiths, H.Samuel, Beaverbrooks) and ask for a professional ring sizing. They use calibrated mandrels and sizing sets for guaranteed accuracy.
โ Highest AccuracyMeasure the inner diameter of an existing ring using digital calipers for sub-millimetre precision. Place caliper jaws inside the ring and read the diameter directly in mm.
โ Highest Accuracyโ ๏ธ Print at 100% scale โ do NOT select "fit to page". Verify the 50 mm mark with a real ruler before cutting.
Cut along the dashed border ยท Wrap around your finger base ยท Mark the overlap ยท Measure the marked length against the ruler above
| UK Size | Diameter (mm) | Diameter (in) | Circ. (mm) | Circ. (in) | US Size | EU Size | Wearer |
|---|
Fingers are largest after a full day. Morning sizes can be ยฝ size smaller.
Cold fingers shrink by up to 1 full size. Always measure at 18โ22ยฐC.
Take 3 separate readings on different days. Use the average for best accuracy.
Measure the exact finger you'll wear the ring on โ every finger differs.
The ring must pass over the knuckle. If it's tight at the knuckle, size up.
Millimetre measurements are far more accurate for ring sizing than inches.
Use paper, card or dental floss โ not elastic or stretchy thread or ribbon.
Bands 5 mm+ sit tighter. Go 1 UK size up for wide or comfort-fit bands.
Your dominant hand is typically ยฝ size larger. Measure the correct hand.
If between two sizes, always choose the larger โ rings can be tightened but not always stretched.
Before using any printed sizer, measure the 50 mm mark with a real ruler to confirm scaling.
For valuable rings, always get professionally sized in-store before ordering.
| Person | Typical UK Range | Diameter Range | Most Accurate Method |
|---|---|---|---|
| ๐ง Child (3โ10 yrs) | A โ E | 11.9 โ 13.2 mm | Paper strip by parent |
| ๐ฉ Teen Girl | F โ J | 13.5 โ 14.9 mm | Paper strip or jeweller |
| ๐ฉ UK Woman (avg) | J โ P | 14.9 โ 16.9 mm | Paper strip (3ร average) |
| ๐จ UK Man (avg) | Q โ V | 17.2 โ 18.9 mm | Paper strip + knuckle check |
| ๐จ Large-Framed Man | W โ Z+ | 19.2 โ 22.2 mm | Jeweller mandrel sizing |