Find your ring size from inside diameter or finger circumference in millimeters, centimeters, or inches. Get the closest US, UK, EU, and JP size in one step.
Find your ring size from diameter or circumference in mm, cm, or inches.
Measure straight across the inside of an existing ring. How to measure ring size
Closest match
US 6.0
UK L 1/2 · EU 52 · JP 12
Next size down: US 5.5 · Next size up: US 6.5
US
6.0
UK
L 1/2
EU
52
JP
12
Diameter (mm)
16.51
Circumference (mm)
51.87
Normalized: 16.50 mm diameter / 51.84 mm circumference. Closest table difference: 0.01 mm. Unit helper: 1 mm = 0.10 cm = 0.039 in.
Choose diameter or circumference and enter mm, cm, or inches.
The calculator converts cm or inches into millimeters for matching.
Results are matched against the site’s ring size chart data.
You can compare full rows in the ring size chart and follow how to measure ring size for more accurate readings.
Millimeters are usually the most precise input for ring sizing. You can also enter centimeters or inches, and the calculator converts the value to millimeters before finding the closest ring size. CM is useful for circumference measurements, and inches are supported for imperial measurements.
Use the full ring size chart for complete size table lookup.
Convert ring sizes between US, UK, EU, and JP systems.
Lookup diameter and circumference values in millimeters.
Print and measure at home to verify your calculator result.
Follow practical steps for accurate diameter and circumference measurements.
If your measurement falls between two sizes, compare both options and consider sizing up for wider bands.
You can also use the ring size converter for direct system-to-system conversions.
Choose diameter or circumference, enter your value in mm, cm, or inches, and the calculator matches it to the closest size row in US, UK, EU, and JP.
Yes. Measure straight across the inside of a ring in mm, cm, or inches, then the calculator converts and matches the closest ring size.
Yes. Measure around your finger with paper or string, enter the circumference, and the calculator maps the closest size in the chart data.
Millimeters are usually the most precise. Inches and centimeters work well too, and the calculator converts them to millimeters before matching.
Compare both nearby sizes and consider sizing up for wider bands or a looser fit. If possible, verify with the printable ring sizer before ordering.
It is a strong estimate when measurements are accurate. For best results, take 2-3 measurements and cross-check with the ring size chart.
Check the matched row in the ring size chart and confirm your measurement with the printable ring sizer and the measurement guide.