TL;DR — Ring gauge is expressed in sixty-fourths of an inch, while case openings are usually listed in millimeters. Convert before ordering: diameter in millimeters equals ring gauge × 25.4 ÷ 64.
By Case & Cedar · Published September 2026
Why the units differ
Cigar makers have described diameter in ring gauge, sixty-fourths of an inch, for more than a century. A 64 ring gauge cigar is one inch across; a 50 is fifty sixty-fourths, or 0.78 inches. Case makers, most of whom work in metric, measure the physical opening or channel in millimeters. The two numbers describe the same thing in different units, so they cannot be compared until one is converted.
The conversion is simple: multiply the ring gauge by 25.4 and divide by 64. A 52 ring gauge becomes 52 × 25.4 ÷ 64 = 20.6 mm. Going the other way, a 22 mm channel is 22 × 64 ÷ 25.4 = 55.4, so it accepts cigars up to about 54 ring gauge with a little room to spare.
Useful conversions
Commit a few to memory and most comparisons become quick: 42 is 16.7 mm, 46 is 18.3 mm, 50 is 19.8 mm, 52 is 20.6 mm, 54 is 21.4 mm, 56 is 22.2 mm, and 60 is 23.8 mm. A channel listed at 22 mm therefore takes a 52 comfortably, a 54 with 0.6 mm to spare, and a 56 not at all.
| Ring gauge | Diameter | Needs an opening of at least |
|---|---|---|
| 42 | 16.7 mm | 18 mm |
| 46 | 18.3 mm | 19.5 mm |
| 50 | 19.8 mm | 21 mm |
| 52 | 20.6 mm | 22 mm |
| 54 | 21.4 mm | 22.5 mm |
| 56 | 22.2 mm | 23.5 mm |
| 60 | 23.8 mm | 25 mm |
Allow tolerance
Published limits may describe a bare opening rather than the usable lined space, and makers measure by hand. Choose an opening at least 1 mm larger than the converted cigar diameter. Cigars also vary: a hand-rolled 52 can measure 53 at the foot, and box-pressed cigars are wider across the flat side than a round cigar of the same nominal gauge.
Tolerance protects the wrapper. Forcing a cigar into a channel that is too narrow scuffs or cracks the wrapper on the way in and, worse, on the way out when the cigar has to be gripped and pulled.
Use both measurements
Diameter does not replace length. A wide cigar can still be too long for the case, and a short cigar can still be too wide for an individual channel. A Churchill at 178 mm × 47 is narrow enough for most channels but too long for a 165 mm case; a gordo at 152 mm × 60 is short enough for almost any case but too wide for a 22 mm channel.
Run both comparisons every time. The case fit checker does it in one step: enter the cigar’s length and ring gauge and the case’s stated maximum length and diameter, and it converts and compares.
Catalog examples
Two cases that publish opening or channel figures, and what those figures mean in ring gauge:
| Case | Capacity | Published fit limits |
|---|---|---|
| Close-Fit Leather 2- or 3-Cigar Travel Case | 2 or 3 | diameter 23 (2-cigar) / 28 (3-cigar) mm |
| Cedar-Lined Leather 5-Cigar Travel Case | 5 | length to 165 mm; diameter 23.5 mm |
| Solid Cedar 4-Cigar Travel Case | 4 | length to 190 mm; diameter 22 mm |
| Horse Motif Leather & Cedar 2- or 3-Cigar Case | 2 or 3 | diameter About 25 mm |
Before ordering, confirm:
- Convert ring gauge to millimeters
- Compare the maximum length
- Leave 1 mm on diameter and 5 mm on length
- Allow extra for box-pressed shapes
- Avoid exact-limit fits
Compare Close-Fit Leather 2- or 3-Cigar Travel Case and Cedar-Lined Leather 5-Cigar Travel Case. Browse all cases →
Frequently asked questions
What is the formula?
Diameter in millimeters = ring gauge × 25.4 ÷ 64. Ring gauge = diameter in millimeters × 64 ÷ 25.4.
A case says ‘fits up to 56 ring gauge’. Is that exact?
It usually means the channel is about 22–23 mm. Treat 54 as comfortable and 56 as the tight upper limit.
Do figurados need a wider opening?
Yes. Measure a torpedo or belicoso at its widest ring gauge; the tapered head does not reduce the channel needed.
Why does my 50 ring gauge cigar feel tight in a 20 mm channel?
A 50 is 19.8 mm, leaving 0.2 mm of clearance before lining and hand variation. Look for 21 mm or wider.
Further reading
- Cigar case dimensions explained
- How to choose a travel cigar case
- Cigar Case Size Guide
- Case Fit Checker
- Ring Gauge Converter
Case & Cedar compares travel cigar cases, cedar-lined storage, and tool organizers by capacity, dimensions, and construction. Browse all cases · Use the size guide.
