TL;DR: Compare the exact two-number specification, not just a name. One inch equals 25.4 mm and one ring gauge equals 1/64 inch in diameter. The reference table separates illustrative formats from manufacturer formats, so 7½ inches is 190.5 mm, not 190 mm.
Why two sources can give different numbers
A general format guide describes a family. A manufacturer catalogue identifies a particular factory format. For example, a 5 × 50 guide Robusto is 127 mm long, while the factory Robustos example is 124 mm by 50. The table keeps both entries with their source and record type.
Use the interactive size chart
Open the 40-record chart and case finder to choose a source-specific example and immediately compare its dimensions with the store’s listed case interiors. CSV and JSON versions preserve the same inputs.
Boundary values must not be rounded into a match
56 ring equals 22.225 mm, exceeding a 22 mm opening. A 6½-inch length is 165.1 mm, exceeding a 165 mm stated maximum. Prominentes is listed at 194 mm, exceeding a 190 mm slot. These are arithmetic comparisons, with no assumption that leather will stretch or a lid will make room.
What to do when the case has no usable measurements
Keep it in the needs-confirmation group. Exterior size includes walls, overlap and inserts. Subtracting 15 or 20 mm from it is a guess, not a fit measurement. Ask for the narrowest opening, usable length and variation before ordering.
For shaped cigars
For tapered shapes, include the intact tip in the length and use the widest body measurement. For a box-pressed cigar, measure its widest cross-section; a nominal round ring gauge alone cannot establish clearance.
References and next step
Use the printable reference card, then the manual checker for a case you own. Manufacturer dimensions remain separate from our supplier-listed case data.
