Ring Size Converter — US, UK, EU, JP
Convert ring sizes between US/Canada, UK/Australia, EU, and Japan systems. Find your ring size in every standard plus inner diameter and circumference in mm.
Related calculators
Frequently asked questions
How do I measure my ring size at home?
Wrap a thin strip of paper around the base of your finger (not the knuckle) and mark where it overlaps. Measure the length in mm — that's your circumference. Use this converter to find your ring size in any system.
Do ring sizes vary by brand?
Most major jewelers and retailers follow standard sizing charts (ISO 8653 in Europe, the Jewelers of America chart in the US). Differences of half a size are common, so when buying online always check the brand's own size guide.
What is the most common ring size?
For women in the US, the most common ring size is 6 (EU 52, UK K½). For men, it's typically 10 (EU 62, UK T½). These are averages — individual sizes vary significantly.
Should I size up or size down if I'm between sizes?
For engagement and wedding rings, size up — a slightly loose ring is easier to resize than one that's too tight. For everyday bands, size down if you prefer a snugger fit.
Does ring size change with temperature?
Yes. Fingers swell in heat and contract in cold. For the most accurate measurement, size yourself at room temperature (around 70°F / 21°C) and in the evening when fingers are slightly swollen from daily activity.