Printable ring sizer

Print a ring sizer in millimeters on Letter or A4: two cut-out strips and circles for ISO sizes 44 to 70. It includes a 100 mm bar so you can confirm the print is true size. Free, with no sign-up.

Your sizer preview

Letter portrait · ISO 44–70 · approximate US sizes shown

Scaled to fit your screen. Do not measure the preview; print the PDF.

Print it at actual size

Download the PDF and load matching Letter or A4 paper.
In the print dialog, choose Actual size or 100%, not Fit or Shrink.
Measure the bar at the top with a real ruler. It must be exactly 100 mm (about 3.94 in). If it is not, do not use the sizer; see printing too small, or check the page with our scale and margin check.

Two ways to measure

Strip: cut out a dashed strip, wrap it snugly around the base of your finger with the numbers facing out, and read the number where the end of the strip meets the scale. That number is your circumference in millimeters, which is your ISO size. Circles: lay a ring you already own flat on the circles. The line is the exact inner diameter, so the inside edge of a ring that fits you should sit on it.

What ISO 8653 sizes mean

ISO 8653:2016, “Jewellery — Ring-sizes — Definition, measurement and designation”, defines the ring size as the inner circumference in millimeters, measured on the largest cylinder that passes through the ring; the standard’s ring stick covers sizes 41 to 76 (catalog entries checked October 19, 2026; the standard itself is paywalled and was not read in full). This sizer covers 44 to 70 and marks each circle with its diameter, which is the size divided by pi. Where you see “about US”, the values come from commonly published retail charts, not from a standard, and sellers’ own charts can differ by up to half a size.

Printable ring size chart: ISO sizes in millimeters and inches

The PDF is a printable ring size chart as well as a sizer. This table lists the same values as the circles on the page: the ISO size is the inner circumference, and the diameter is that size divided by pi. Inch values are the millimeter values divided by 25.4. The US column is approximate and comes from commonly published retail charts, so check the seller’s own chart.

ISO ring sizes 44 to 70 with circumference and inner diameter in millimeters and inches, and approximate US size
ISO size (circumference, mm)	Circumference (in)	Inner diameter (mm)	Inner diameter (in)	About US size
44	1.73	14.0	0.551	3
45	1.77	14.3	0.564	3½
46	1.81	14.6	0.576	3½
47	1.85	15.0	0.589	4
48	1.89	15.3	0.602	4½
49	1.93	15.6	0.614	5
50	1.97	15.9	0.627	5½
51	2.01	16.2	0.639	5½
52	2.05	16.6	0.652	6
53	2.09	16.9	0.664	6½
54	2.13	17.2	0.677	7
55	2.17	17.5	0.689	7
56	2.20	17.8	0.702	7½
57	2.24	18.1	0.714	8
58	2.28	18.5	0.727	8½
59	2.32	18.8	0.739	9
60	2.36	19.1	0.752	9
61	2.40	19.4	0.764	9½
62	2.44	19.7	0.777	10
63	2.48	20.1	0.790	10½
64	2.52	20.4	0.802	11
65	2.56	20.7	0.815	11
66	2.60	21.0	0.827	11½
67	2.64	21.3	0.840	12
68	2.68	21.6	0.852	12½
69	2.72	22.0	0.865	12½
70	2.76	22.3	0.877	13

Limits

This is a guide, not a fitting. Measure when your hands are warm and toward the end of the day, repeat on two or three days, and allow for a wider knuckle. Wide bands fit tighter than thin ones. If the ring is expensive, a gift or hard to resize, confirm the size with a jeweller. The PDF dimensions are checked digitally; physical printer output has not been tested.

Your choices stay on this device; see privacy and anonymous download measurement. To measure other things, print a printable ruler. More tools are in the printer tools hub.

Good questions

How accurate is a printed ring sizer?

It is a guide. It is only as accurate as the print, so confirm the 100 mm bar measures 100 mm with a real ruler first. Paper stretches and fingers change size, so for an expensive or hard-to-resize ring, have a jeweller measure you.

What do the numbers mean?

Under ISO 8653 a ring size is the inner circumference of the ring in millimeters, so ISO 54 is 54 mm around. Divide by pi (3.1416) to get the inner diameter: 54 mm around is about 17.2 mm across. The circles and strip use these exact values.

How do I convert to a US size?

There is no official source for US sizes. The optional US labels use commonly published retail chart values, rounded to the nearest half size, and charts from different sellers differ by up to about half a size. Treat them as approximate and check the seller’s own chart before buying.

When should I measure my finger?

Measure when your hands are warm and toward the end of the day, because fingers are smaller when cold and larger in the evening or after heat. If your knuckle is bigger than the base of the finger, measure both and choose a size that slides over the knuckle but stays snug at the base.

Are my choices uploaded or saved?

The sizer is generated in your browser. Your choices are not saved or uploaded. The site can count anonymous PDF download clicks using the paper size; the privacy page explains the opt-out.