A Montblanc catalogue number tells you nothing — we checked 252 of them

Buying a fountain pen online, you often face a row of near-identical listings separated only by a catalogue number. How readable that number is varies enormously by brand.

Line four brands up and their philosophies separate sharply.

Pilot — spelled out in letters

Both colour and nib are letters. You can read most of a pen from the number alone. The friendliest of the four.

The catch: the letters are initials of colour names, so the same letter means a different colour on a different model.

Sailor — packed into three digits

Of the last three digits, the first is the nib and the other two the colour. The nib reads cleanly from the digit — the larger the number, the broader the line, from extra fine up to broad.

Colour does not travel between series. A little more work than Pilot's letters.

Platinum — decoded only partway

Colour number and nib number, joined by a hyphen. Structurally close to Sailor.

But only three of the nib digits have ever been confirmed. The others exist on real pens with no known meaning. Of the three systems, this is the least solved.

Montblanc — nothing to read

Then there is Montblanc, whose numbers are simply six digits.

Cross-referencing 252 pens turns up no rule for colour and none for nib. No tendency for larger numbers to mean broader nibs. Not even a running sequence.

The natural reading is that a Montblanc number is not meant for customers at all — it is an internal identifier assigned pen by pen. To buy the nib you want, you read the description, not the number.

Readability is a statement of intent

Some brands want the number read as words, some compress it into digits, and some never intended it to be read.

A readable catalogue number implies a company that expects customers to look at catalogue numbers. If your pens are sold across a counter with a salesperson explaining them, as Montblanc's largely are, there is no reason to make the number talk.

(Compiled from the fountain pens of each brand recorded in PencilDB, August 2026.)