Zero-Slip Ring Sizer

Ensure millimeter-perfect accuracy, then lock the screen to measure your ring without accidental swiping.

If you know your exact device specifications, enter the screen size.

inches
🔒
100% Private & Secure

This tool runs entirely offline in your web browser. No camera permissions are required, and zero personal data is ever uploaded or saved.

🎯
Mathematically Perfect

By using the global ISO 7810 credit card standard for calibration, our algorithm mathematically eliminates screen-size errors down to the sub-millimeter.

How to find your exact ring size online (without the screen slipping)

If you've ever tried placing a metal engagement ring or wedding band on a standard digital ruler, you probably noticed the screen swiping, zooming, or scrolling away. This happens because modern capacitive touch screens react to conductive metals the same way they react to your fingers.

The "Zero-Slip" Lock Screen Advantage

Our actual size online ring sizer uses a dedicated Lock Screen mode. When you click "Lock Screen & Measure," we apply a strict rule. Allowing you to slide your ring around the screen to match the circle.

How to measure accurately:

  1. Calibrate: Use a standard credit card (which is universally 85.6mm wide) to calibrate the screen. This guarantees sub-millimeter accuracy regardless of what phone or monitor you are using.
  2. Lock: Enter the locked measuring mode.
  3. Place & Match: Place a ring that fits you well flat against the screen. Adjust the slider until the golden circle perfectly touches the inside edge of your physical ring.
  4. Read: Choose your region from the dropdown to see your exact size.

International Ring Size Conversion Chart

Use our static chart below to quickly convert between US, India, UK, and EU ring sizes based on inner diameter.

Diameter (mm) US / Canada India UK / Australia EU (Circumference)
14.0 mmSize 3Size 5F44
14.8 mmSize 4Size 7H 1/247
15.7 mmSize 5Size 10J 1/249
16.5 mmSize 6Size 12M52
17.3 mmSize 7Size 15O54
18.1 mmSize 8Size 17Q57
18.9 mmSize 9Size 20S60
19.8 mmSize 10Size 22T 1/262
20.6 mmSize 11Size 25V 1/265
21.4 mmSize 12Size 27Y67

Expert Tips for Measuring Your Ring Size at Home

When is the best time of day to measure?

Your fingers change size throughout the day based on temperature and hydration. For the most accurate reading, measure your fingers at the end of the day when they are warm. Cold fingers can shrink up to half a size.

What should I do if I am between two sizes?

If your measurement falls exactly between two sizes, it is always recommended to size up. A ring that is slightly loose is much easier to resize down than a tight ring is to resize up, and it accounts for natural finger swelling during warmer months.

Does the width of the band matter?

Yes. Thicker bands (over 4mm wide) feel tighter on the finger than thin bands. If you are measuring a thin ring but plan to buy a thick, chunky band, you may want to order a quarter or half size larger than your measurement.