Ring gauge to millimeters

Last updated: August 21, 2026

Cette page existe aussi en français.

A cigar’s ring gauge is its diameter expressed in sixty-fourths of an inch. A ring gauge of 50 means 50/64 of an inch. Because the rest of the world measures in millimeters, the two notations sit side by side on most cigar sheets — including those in Cigarino.

The conversion is arithmetic, and exact:

diameter in millimeters = ring gauge ÷ 64 × 25.4

One inch is 25.4 millimeters by definition, so a single ring gauge point is 0.397 mm. The table below rounds to one decimal, which is finer than any cigar is actually made.

Conversion table

Ring gauge	Millimetres	Inches
30	11.9 mm	0.469 in
31	12.3 mm	0.484 in
32	12.7 mm	0.500 in
33	13.1 mm	0.516 in
34	13.5 mm	0.531 in
35	13.9 mm	0.547 in
36	14.3 mm	0.563 in
37	14.7 mm	0.578 in
38	15.1 mm	0.594 in
39	15.5 mm	0.609 in
40	15.9 mm	0.625 in
41	16.3 mm	0.641 in
42	16.7 mm	0.656 in
43	17.1 mm	0.672 in
44	17.5 mm	0.688 in
45	17.9 mm	0.703 in
46	18.3 mm	0.719 in
47	18.7 mm	0.734 in
48	19.1 mm	0.750 in
49	19.4 mm	0.766 in
50	19.8 mm	0.781 in
51	20.2 mm	0.797 in
52	20.6 mm	0.813 in
53	21.0 mm	0.828 in
54	21.4 mm	0.844 in
55	21.8 mm	0.859 in
56	22.2 mm	0.875 in
57	22.6 mm	0.891 in
58	23.0 mm	0.906 in
59	23.4 mm	0.922 in
60	23.8 mm	0.938 in

Millimetres to ring gauge

The same relation, read the other way:

ring gauge = diameter in millimeters ÷ 25.4 × 64

A cigar measured at 19.8 mm is therefore a ring gauge of about 50, and one at 16.7 mm about 42. Ring gauges are always whole numbers, so round to the nearest one.

What the numbers correspond to

Ring gauge alone does not name a shape — length matters as much — but the common formats sit in recognisable bands. These are the ranges given on our cigar glossary:

Panetela	34 to 38	13.5 to 15.1 mm
Corona	42 to 44	16.7 to 17.5 mm
Churchill	47 to 50	18.7 to 19.8 mm
Robusto	48 to 52	19.1 to 20.6 mm
Toro	50 to 54	19.8 to 21.4 mm

The full vocabulary — vitola, shape, wrapper, binder, filler, strength — is defined on the cigar glossary.