Ring Sizer

Measure finger size and convert international ring standards.

Audited & Calibrated: May 2026|100% Client-Side Private Processing

Ring Diameter:16.5 mm

11mm23mm

Ring Diameter Input

The diameter is the distance across the inside of the ring. Use the slider above or enter a precise value to find your international size.

Calculated Output

Estimated US/CA Size

6.0

Circumference: 51.8mm

European (EU)

United Kingdom (UK)

F ½

Japanese (JP)

Global Jewelry?

Planning to buy jewelry from abroad?

"Use the Currency Converter to see the price in your local currency and save on conversion fees."

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Ring Size Calculator: Your Guide to Choosing the Perfect Size with Confidence

Have you found the perfect ring online but are hesitant to buy it for fear of the wrong size? CalQube's ring size calculator helps you convert circumference or diameter measurements into internationally recognized ring sizes (US, UK, and EU) with extreme accuracy.

How to measure your finger size at home?

To get an accurate result using the CalQube calculator, follow these simple steps to measure your finger circumference:

1. Use string or paper

Wrap it around the base of the finger where you want to wear the ring.

2. Mark meeting point

Use a pen to mark the point where one end of the string meets the other.

3. Measure with ruler

Place it on a ruler and measure the distance in millimeters (mm).

4. Enter result

Enter the circumference or diameter, and sizes will display instantly.

International Conversion Chart

Standard relationship between circumference, diameter, and global sizing.

Circumference (mm)	Diameter (mm)	US Size	UK Size
44.2	14.1	3	F
47.7	15.2	4	H
51.0	16.2	5	J
54.4	17.3	7	N ½
57.9	18.4	9	R ½
60.8	19.3	10	S

Golden Tips for Accuracy

Timing is key

Measure your finger at the end of the day when it's largest, and avoid measuring when your hand is cold.

Consider the knuckle

The ring should be snug enough to stay in place, but loose enough to slide over the knuckle.

Dominant Hand

Fingers of your writing hand are often slightly larger. Measure the correct hand!

Ring Width

Very wide rings may need to be a slightly larger size than thinner ones for comfortable movement.

FAQ

What if my measurements fall between two sizes?

We always recommend choosing the larger size for comfort, as finger size fluctuates with seasons.

Are men's and women's ring sizes different?

No, the sizing system is standardized. Women's sizes typically range from 3-9, while men's range from 8-14.

ℹ️ Note:

While the CalQube calculator is accurate, the most reliable way to get a definitive size is to visit a local jeweler and use a professional metal measuring tool.

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