Ring Size Chart & Converter – Find Your Perfect Fit

The Ring Size Chart & Converter helps you accurately determine your ring size and convert between sizing systems used worldwide. Whether you’re ordering rings online, measuring at home, or comparing international sizes, this tool ensures you find the perfect fit with confidence.

Why Finding the Right Ring Size Matters

• Comfort: A correctly sized ring feels natural and stays securely on your finger.
• Accuracy for online shopping: Avoid returns by knowing your correct size before ordering.
• International compatibility: Different countries use different ring size systems—conversion prevents confusion.
• Jewelry customization: Proper measurements are essential for custom or engraved rings.

Who This Converter Is For

Shoppers, jewelers, designers, gift-givers, and anyone needing precise sizing for personal or professional use.

Major Ring Size Systems Supported

• US/Canada (numeric sizes like 5, 6.5, 7, etc.)
• UK/Australia (alphabetic sizes like J, K, L½, M)
• Europe (EU sizes, based on inner circumference in mm)
• Japan (numeric scale)
• Switzerland
• ISO Standard (inner circumference in millimeters)

Common Conversion Factors

Most conversion systems revolve around two measurements:

• Inner circumference (mm): measured around the inside of the ring.
• Inner diameter (mm): measured straight across the inside of the ring.

Formula:
Inner Circumference = Diameter × π

How to Measure Your Ring Size at Home

1. Wrap a thin strip of paper or string around the base of your finger.
2. Mark where the ends meet.
3. Lay it flat and measure the length in millimeters—this is the inner circumference.
4. Use the chart or converter to find the corresponding ring size.

Ring Size Chart (Sample Values)

US/CA	UK/AU	EU (mm)	Diameter (mm)	Japan
5	J½	49.3	15.7	9
6	L	51.9	16.5	12
7	N	54.4	17.3	14
8	P	56.9	18.2	16
9	R	59.5	19.0	18

Step-by-Step Conversion Example

Problem: Convert a US size 7 to UK and EU equivalents.
Step 1: US 7 corresponds to inner circumference ≈ 54.4 mm.
Step 2: In the UK system, US 7 ≈ size N.
Step 3: In the EU system, 54.4 mm circumference ≈ size 54.
Answer: US 7 = UK N = EU 54.

How the Converter Works (User Flow)

1. Select your known size (e.g., US size 6.5).
2. Choose the original system (US, UK, EU, Japan, etc.).
3. Select the target sizing system(s) for conversion.
4. Click “Convert” — the tool maps your size to the matching circumference/diameter and outputs all equivalents.
5. Optional: enables half-sizes, quarter-sizes, and exact millimeter measurements.

Input Notes & Validation

• Supports full, half, and quarter sizes (e.g., US 7.25).
• Metric inputs must be in millimeters, not centimeters.
• Sizes vary slightly by jeweler—actual fit may differ by up to 0.2 mm.
• Finger size changes with temperature, humidity, and time of day.

Practical Tips for Accurate Sizing

• Measure your finger at the end of the day when it’s largest.
• Avoid measuring when your hands are cold (fingers shrink).
• Measure the knuckle too—your ring must slide past it comfortably.
• Wide bands fit tighter; consider sizing up for rings thicker than 6 mm.
• If between sizes, choose the slightly larger one for comfort.

Limitations & Considerations

• International standards vary slightly; conversions are approximate.
• Printed charts must be printed at 100% scale for accurate measurement.
• Always confirm size by trying a physical ring sizer for expensive jewelry.

FAQs – Ring Size Chart & Converter

1. How do I measure without a ring sizer?
Use paper/string and measure its mm length around your finger, then match to a chart.

2. Are ring sizes unisex?
Yes — men’s and women’s rings use the same sizing systems.

3. What’s the most accurate method?
A jeweler’s metal ring sizer provides the most precise measurement.

4. Can I convert UK sizes to US?
Yes — the tool maps alphabetic UK sizes to numeric US sizes based on circumference.

5. Does temperature affect size?
Yes — fingers shrink in cold and swell in heat.

6. What if my measurement is between sizes?
Choose the larger size or look for quarter-size options.

7. Are half-sizes available in all countries?
No — some systems (like EU) use whole sizes only based on millimeters.

8. Do men and women use different conversion charts?
No — sizing systems are universal regardless of gender.

9. How accurate are online ring size charts?
They are accurate when printed properly, but physical sizers are most reliable.

10. Can I use a ring that already fits to find my size?
Yes — measure the inner diameter of the ring and convert using the chart.

Quick Disclaimer

This Ring Size Chart & Converter provides approximate conversions across international systems. Actual fit can vary slightly by manufacturer, ring design, and individual finger shape. For high-value or custom jewelry, have your finger sized professionally.