Find Your Perfect Ring Size

Free online tool to measure your ring size accurately at home

What You'll Need

Card or Ruler

Use a bank card or physical ruler to calibrate your screen

Required

A Ring That Fits

A ring that fits the finger you want to measure. Place it on screen to find your size.

Optional

Tips for Best Results

Place your card flat against the screen, not tilted
Measure at room temperature when fingers are normal size
If buying online, consider going 0.5 size up for comfort

Ring Size Conversion Chart

ISO/DE	Inner Diameter	US/CA	UK/AU	IT/ES/CH	RU
44	14.0 mm	3	F	4	14
45	14.3 mm	3½	G	5	14.5
46	14.6 mm	3½	H	6	14.5
47	15.0 mm	4	H½	7	15
48	15.3 mm	4½	I½	8	15.5
49	15.6 mm	5	J	9	15.5
50	15.9 mm	5½	K	10	16
51	16.2 mm	5½	L	11	16
52	16.6 mm	6	L½	12	16.5
53	16.9 mm	6½	M½	13	17
54	17.2 mm	7	N	14	17
55	17.5 mm	7½	O	15	17.5
56	17.8 mm	7½	P	16	18
57	18.1 mm	8	P½	17	18
58	18.5 mm	8½	Q½	18	18.5
59	18.8 mm	9	R	19	19
60	19.1 mm	9	S	20	19
61	19.4 mm	9½	T	21	19.5
62	19.7 mm	10	T½	22	19.5
63	20.1 mm	10½	U½	23	20
64	20.4 mm	11	V	24	20.5
65	20.7 mm	11	W	25	20.5
66	21.0 mm	11½	X	26	21
67	21.3 mm	12	X½	27	21.5
68	21.6 mm	12½	Y½	28	21.5
69	22.0 mm	12½	Z	29	22
70	22.3 mm	13	Z½	30	22.5
71	22.6 mm	13½	Z1	31	22.5
72	22.9 mm	14	Z2	32	23

Frequently Asked Questions

When properly calibrated with a bank card, our tool provides measurements accurate to within 0.5mm, which is sufficient for most ring purchases.

Bank cards follow the ISO/IEC 7810 ID-1 standard with exact dimensions of 85.6mm × 53.98mm. This standardized size allows us to calculate the exact pixel-to-millimeter ratio on your screen.

Yes! Our tool works on any device with a screen. Just make sure to calibrate with your bank card on the device you're using.

You can measure your finger circumference directly using a strip of paper or string. Wrap it around your finger, mark the overlap, and measure the length.

Each region uses a different sizing system. US sizes use numbers (typically 3-13), UK sizes use letters (A-Z), and EU sizes are based on the inner circumference in millimeters. Our tool converts between all systems automatically.

Yes, fingers can swell due to heat, exercise, salt intake, or time of day. For the most accurate measurement, measure in the evening when fingers are slightly larger, and avoid measuring when very cold or after exercise.

If you're between sizes, it's generally better to round up to the larger size for comfort. Rings that are slightly loose are easier to wear than ones that are too tight, especially in warm weather.

Borrow a ring they already wear on the intended finger and measure it with our tool. Alternatively, trace the inside of their ring on paper, or press it into a bar of soap to get an impression you can measure later.