Online Ring Sizer Tool

Find an estimated ring size in under a minute. Choose how you want to measure.

What do you want to do?

1Calibrate screen

2Match ring

3Get estimated size

Step 1 of 3

Calibrate your screen

Start with a quick screen calibration, then place an existing ring flat on the measurement circle.

Open the dedicated tool page for the full interactive measurement area and a clearer step-by-step workspace.

Calibrate your screen for more useful measurements.

Follow the simple steps to measure or match your ring.

See your estimated size across major standards.

Tools

Use a second method when the result matters. Measuring twice is the easiest way to avoid ordering the wrong ring size.

This tool provides an estimated ring size only. Double-check before buying, especially for expensive, custom, or engagement rings.

Enter diameter or circumference in millimeters.

Convert between US, UK, EU, JP, and CN sizes.

Download A4 and US Letter PDF guides.

Compare standard size references in one table.

Quick chart

US	UK	EU	JP	CN	Diameter	Circumference
5	J	49	9	9	15.7 mm	49.3 mm
5.5	K	51	10	10	16.1 mm	50.6 mm
6	L	52	12	12	16.5 mm	51.9 mm
6.5	M	53	13	13	16.9 mm	53.1 mm
7	N	54	14	14	17.3 mm	54.4 mm
7.5	O	56	15	15	17.7 mm	55.7 mm
8	P	57	16	16	18.1 mm	57 mm
8.5	Q	58	17	17	18.5 mm	58.3 mm

FAQ

How accurate is this ring size tool?

It provides an estimated ring size. Screen calibration, browser zoom, ring alignment, and measuring method can all affect the result.

Can I measure ring size on my phone?

Yes. A phone is often easier because you can place a ring directly on the screen after calibration.

What if I am between two sizes?

Check the fit with another method. Wider bands can feel tighter, so many buyers choose the larger nearby size for wide rings.

Should I use this for an engagement ring?

Use it as a starting point only. For expensive, custom, or engagement rings, confirm with a professional jeweler.