Yvert, Michel, Scott, Stanley Gibbons: understanding stamp catalogues and catalogue numbers
"Yvert 176", "Michel 157", "SG 399", "Scott 191": these four references all point to the same stamp, a blue 50-centime Pasteur from France, 1923. There is no universal stamp number. Each catalogue has built its own numbering, and that is the language collectors, dealers and auction houses use to understand each other. Here is how to find your way around.
The major catalogues
Every country with a philatelic tradition has its reference catalogue. The four most widely used worldwide:
| Catalogue | Published in | Abbreviation | Values in | Strengths |
|---|---|---|---|---|
| Yvert et Tellier | France (Amiens) | YT, Yt, Y&T | euros | the reference in France, Monaco and for the former French colonies |
| Michel | Germany (Munich) | Mi | euros | the most detailed, the reference in Germany and throughout Central Europe |
| Stanley Gibbons | United Kingdom (London) | SG | pounds sterling | the reference for the UK and the Commonwealth |
| Scott | United States | Sc, Sn | dollars | the reference in North America |
Other national catalogues are authoritative at home: Unificato and Sassone in Italy, Edifil in Spain, COB in Belgium, NVPH in the Netherlands, Zumstein in Switzerland, Facit in the Nordic countries, Sakura in Japan. For their own country's stamps they are often more precise than the worldwide catalogues.
How to read a number
Numbered country by country, in chronological order
Each catalogue numbers stamps country by country, in order of issue: number 1 is the country's first stamp. In France, Yvert 1 is the 10 c bistre Ceres of 1850 (the black 20 c of 1849 is no. 3). A number on its own therefore means nothing: always state the country, then the catalogue.
Separate series for special stamps
Stamps outside ordinary postage have their own numbering, marked by a prefix or a section. In Yvert: PA for airmail, Taxe for postage dues, Préo for precancels, BF for souvenir sheets, Service for official stamps, and a separate section for booklets. Scott puts letters before the number: C (airmail), J (postage due), B (semi-postal). Stanley Gibbons marks souvenir sheets MS (miniature sheets). "PA 14" and "14" are two different stamps.
Letters: varieties and inserted numbers
A letter after the number usually signals a variant of the main stamp: another colour, perforation, paper or engraving type. Our 1853 Napoleon III 1 F, for instance, is Yvert 18 but Michel 17a. Some letters are also used to insert a stamp discovered or classified later, without renumbering the whole country.
The two Marianne de Cheffer above are a good example: same design, same value, same colour, but two different Yvert numbers because the perforation differs. To tell them apart, read Perforations and watermarks: telling identical stamps apart.
Catalogues don't split things the same way
Catalogues disagree on what deserves its own number. What Yvert treats as a simple variety (a letter) may have a full number in Michel, and vice versa. That is why there is no perfect correspondence from one catalogue to another, only approximate concordance tables. For classic British stamps, Stanley Gibbons even distinguishes printing plates: the 1840 Penny Black was printed from plates numbered 1 to 11, which specialists collect separately.
The WNS number, an official identifier since 2002
Since 2002, the Universal Postal Union has kept the WNS (WADP Numbering System), an official register of stamps issued by its member countries. Each stamp gets a number of the form FR001.02: the country code, a sequence number, then the last two digits of the year. It is the only identifier shared by every country, but it only covers issues since 2002 and gives no catalogue values.
How to record the references of your collection
- Pick one reference catalogue per country: Yvert for France, Michel for Germany, Stanley Gibbons for the UK… and stick to it. Mixing numbering systems in the same album is the surest way to create duplicates.
- Always record the full trio: country, catalogue, number. "France YT 176" is unambiguous, "176" is not.
- Keep letters and prefixes: "1536Ab" is not "1536", "PA 14" is not "14". The difference in value can be significant.
- Note the edition year of the catalogue you use for values: values change from one edition to the next, and occasionally a publisher renumbers a period.
- Add the references from other catalogues when you know them: they help as soon as you deal with a collector abroad or browse an auction.
References on our stamp pages
Each page of our catalogue shows, when known, the Yt (Yvert et Tellier), Mi (Michel), SG (Stanley Gibbons) and Sn (Scott) references. The prefix in front is the country code: "FR 176" reads "France no. 176". The easiest way is to take a photo of your stamp: the matching page gives you its numbers in the main catalogues at once. To estimate what it is worth, see How much is my stamp worth?.