Ring Size Calculator
Convert finger circumference or diameter to US, UK, and EU ring sizes.
US ring size
7
Breakdown
- Inner diameter (mm)
- 17.20
- UK / Australia
- O
- EU (circumference mm)
- 54
Last updated:
FAQ
How do I measure my ring size at home?
Wrap a strip of paper around the finger, mark the overlap, and measure the length in millimeters — that is your circumference.
Should I size up for wide bands?
Yes — bands wider than about 6 mm sit tighter, so add a half size to the measured size for comfort.
Why do my fingers change size during the day?
Fingers swell in heat and shrink in cold; measure in the evening at room temperature for the most reliable reading.
Related Calculators
Tip Calculator
→Calculate the tip amount and total bill per person, with smart service-quality presets and rounding options.
Split the Bill Calculator
→Split a bill fairly between friends, with optional tip and separate handling of shared vs personal items.
GPA Calculator
→Calculate your grade point average on a 4.0 scale from course grades and credit hours, with cumulative GPA support.
Grade Calculator
→Find what you need on the final exam to reach your target course grade, based on current grade and exam weight.