Free Ring Size Calculator
A ring size calculator converts finger circumference or inside ring diameter into matching US, UK, EU, diameter, and circumference sizes.
Measure in millimeters, choose a fit allowance, and compare the closest gold ring size before ordering a band, engagement ring, wedding ring, or gift.
Suggested size
US
7
EU
54
UK: O
Diameter: 17.3 mm
Measure your ring size online
Adjusted measurement
55.0 mm circumference
That equals about 17.5 mm inside diameter after the selected fit allowance.
Ring size conversion result
US
7
UK
O
EU
54
Diameter
17.3 mm
Closest chart match: 54.4 mm circumference. Your adjusted measurement is 0.6 mm above that chart size.
Common ring size notes
Most women's rings
US 5-7A practical starting range for gifts when you cannot measure directly.
Most men's rings
US 8-11Wider bands often need a half size more than slim bands.
Stacking rings
Half size upStacked rings feel tighter because they cover more of the finger.
Ring size chart
| US | UK | EU | Diameter | Circumference |
|---|---|---|---|---|
| 3 | F | 44 | 14.1 mm | 44.2 mm |
| 3.5 | G | 45 | 14.5 mm | 45.5 mm |
| 4 | H | 47 | 14.9 mm | 46.8 mm |
| 4.5 | I | 48 | 15.3 mm | 48.0 mm |
| 5 | J 1/2 | 49 | 15.7 mm | 49.3 mm |
| 5.5 | L | 51 | 16.1 mm | 50.6 mm |
| 6 | M | 52 | 16.5 mm | 51.9 mm |
| 6.5 | N | 53 | 16.9 mm | 53.1 mm |
| 7 | O | 54 | 17.3 mm | 54.4 mm |
| 7.5 | P | 56 | 17.7 mm | 55.7 mm |
| 8 | Q | 57 | 18.1 mm | 57.0 mm |
| 8.5 | Q 1/2 | 58 | 18.5 mm | 58.3 mm |
| 9 | R 1/2 | 59 | 19.0 mm | 59.5 mm |
| 9.5 | S 1/2 | 61 | 19.4 mm | 60.8 mm |
| 10 | T 1/2 | 62 | 19.8 mm | 62.1 mm |
| 10.5 | U 1/2 | 63 | 20.2 mm | 63.4 mm |
| 11 | V 1/2 | 64 | 20.6 mm | 64.6 mm |
| 11.5 | W 1/2 | 66 | 21.0 mm | 65.9 mm |
| 12 | Y | 67 | 21.4 mm | 67.2 mm |
| 12.5 | Z | 68 | 21.8 mm | 68.5 mm |
| 13 | Z+1 | 70 | 22.2 mm | 69.7 mm |
How to measure ring size
Measure in millimeters
Wrap a thin strip of paper around the finger or measure the inside diameter of a ring that already fits.
Use the calculator
Enter circumference or diameter, then choose exact, comfort, or wide-band fit.
Confirm before buying
Check the result against the chart and resize slightly for heat, cold, swelling, or wide bands.
Pricing a gold ring too?
Use Gold In Egypt to compare current Egyptian gold prices after you know the size and estimated ring weight.
Related gold tools
Browse all toolsRing size calculator FAQ
Measure finger circumference or inside ring diameter in millimeters, enter it into the calculator, and use the closest US, UK, or EU chart match.