If you collect world banknotes, it does not take long before you encounter numbers such as P#, B#, TBB#, Fr#, or N#. The same banknote may even have several different numbers depending on where you look.
These numbers help collectors, dealers, auction houses, grading companies, and researchers identify a particular banknote type or variety more precisely than simply describing it by country, denomination, and year.
The confusing part is that there is no single universal numbering system for every banknote. Different catalogs use their own systems, specialized references may provide greater detail for certain countries, and online databases such as Numista and Colnect maintain their own identifiers while also cross-referencing published catalogs.
Here is a guide to some of the references you are most likely to encounter.
Pick Numbers and the Standard Catalog of World Paper Money
For decades, one of the most important references for world banknotes was the Standard Catalog of World Paper Money (SCWPM), originally compiled by German numismatist Albert Pick and later published by Krause Publications.
This is where the familiar Pick number, usually written P#, comes from.
A reference such as:
P# 91
identifies a particular banknote type listed in the Standard Catalog of World Paper Money. Letters may also follow the number to distinguish varieties, such as different dates, signatures, or printings.
Pick numbers became so widely used that they effectively developed into a common language among world-banknote collectors. They remain common in dealer inventories, auction listings, older reference books, collection records, and on some third-party grading labels.
The difficulty today is that the Standard Catalog of World Paper Money is no longer an actively maintained reference for newly issued notes. Its three major volumes ended publication at different times. The General Issues, 1368–1960 volume reached its 16th edition in 2016, Specialized Issues its 12th edition in 2013, and Modern Issues, 1961–Present reached its 25th edition in 2019.
That does not make existing Pick numbers obsolete. For banknotes already cataloged by SCWPM, the Pick number remains an important and widely recognized reference. It does, however, create a problem for newly issued banknotes.
Be Careful with “New” Pick Numbers
Collectors may occasionally encounter Pick-style numbers assigned to banknotes issued after publication of the SCWPM ended.
These should be treated cautiously.
Various dealers, websites, and collectors have continued using or assigning Pick-style numbers to newer notes, but these may not represent numbers actually published in the Standard Catalog of World Paper Money. Different sources can therefore assign conflicting numbers to the same newer issue.
For recent banknotes, it is better to verify whether a Pick number was actually published rather than assuming that any number beginning with “P” is an official SCWPM reference. Fortunately, another catalog has increasingly filled the gap.
The Banknote Book: B# and TBB#
The Banknote Book, created by Owen W. Linzmayer and now published by Greysheet, has become an important modern reference for world paper money.
Rather than periodically publishing one enormous printed world catalog, The Banknote Book is organized into individual country chapters that can be updated as new information, issues, and varieties become available.
The catalog uses numbers beginning with B, such as:
B123
Additional letters may identify individual varieties within a type.
The numbering system was developed along similar lines to Pick while addressing some of the limitations encountered with the older catalog. The Banknote Book also cross-references corresponding Pick numbers when they exist, making it particularly useful for collectors transitioning between the two systems.
Why Does Numista Call It TBB#?
This can initially be confusing.
The actual catalog number used by The Banknote Book begins with B. However, an online database needs to identify which reference catalog the number comes from.
Numista identifies The Banknote Book reference using TBB#. Therefore, collectors may encounter a reference identified by Numista as TBB#, while the number in The Banknote Book itself is a B-number.
The important distinction is:
B# = the catalog number used by The Banknote Book
TBB# = a reference label used by Numista to identify The Banknote Book as the source
For collectors of recently issued world banknotes, The Banknote Book is particularly useful because it continues to document new issues and varieties that appeared after publication of SCWPM ended.
Numista Numbers: N#
Numista is somewhat different because it is an online numismatic catalog and collection database, rather than simply another printed reference catalog.
Every item entered into Numista receives a unique identifier:
N#
For example:
N# 123456
The N# permanently identifies that particular entry in the Numista database. It does not replace external references such as Pick or The Banknote Book.
In fact, one of Numista’s strengths is its ability to include multiple catalog references for the same banknote.
A Numista entry might therefore contain:
N# 123456
P# 45
TBB# 210
These numbers are not competing with one another. They identify or reference the same banknote through different systems. Numista’s cataloging guidelines specifically allow multiple references and recommend that newer, more authoritative, and more exhaustive standard references receive priority.
Friedberg Numbers: Fr#
Collectors of United States paper money will frequently encounter another reference:
Fr#
This refers to the Friedberg numbering system used in Paper Money of the United States, originally developed by Robert Friedberg and continued through subsequent editions by Arthur L. and Ira S. Friedberg.
Friedberg numbers are widely used to identify United States federal paper money and can distinguish notes based on characteristics such as series, signatures, seals, issuing banks, and other important varieties.
For collectible U.S. federal paper money, Friedberg is generally the more familiar specialized reference system.
Specialized Banknote Catalogs
Pick, The Banknote Book, and Friedberg are far from the only banknote references available.
Many countries and specialized collecting areas have their own catalogs. These can sometimes provide significantly greater detail than a worldwide reference.
Depending on the catalog, individual references may distinguish between:
- signature combinations;
- serial-number prefixes;
- issue dates;
- printing varieties;
- replacement notes;
- security-feature changes;
- printers;
- commemorative issues; and
- minor design changes.
For someone specializing in a particular country or series, a respected specialized catalog may therefore provide more precise information than a general world-banknote reference.
This is another reason why a single banknote can legitimately have several different catalog numbers.
What About Colnect?
Colnect is another online collection database frequently used by banknote collectors.
Like Numista, it can be useful when researching individual dates, signatures, prefixes, issues, and varieties. However, it is helpful to distinguish between an online database identifier and a number originating in an established reference catalog.
Databases such as Numista and Colnect can help collectors identify, organize, and research their notes while also providing information from other references. Published and maintained catalogs such as The Banknote Book, Friedberg, or specialized national catalogs provide their own independent numbering systems.
Both can be useful, but they serve somewhat different purposes.
Why Can the Same Banknote Have Different Numbers?
Different catalogs do not always agree about what constitutes a separate banknote type or variety.
Imagine a banknote introduced in 2020. The basic design remains unchanged, but another printing appears in 2025 with different signatures and a new serial-number prefix.
One catalog might treat both as varieties of the same basic banknote.
Another might distinguish the 2025 printing more specifically.
An online database might separate the information even further so collectors can track each variation individually.
None of these approaches is necessarily incorrect. They simply reflect different cataloging systems and philosophies.
This is also why the date printed on a banknote does not always tell the entire story. A note carrying a printed date of 2020 might have been produced or issued several years later with different signatures, serial prefixes, or other identifiable characteristics.
Which Reference Number Should You Use?
There is no requirement that collectors choose only one reference system.
For older world banknotes, an established Pick number remains extremely useful because it is so widely recognized. Adding the corresponding Banknote Book number can provide another current reference.
For newer world banknotes, The Banknote Book B-number may be a better primary reference, particularly when the note was issued after SCWPM ceased publication and no genuine published Pick number exists.
For United States federal paper money, Friedberg numbers remain an important specialized reference.
For specialized collections, a respected country- or series-specific catalog may provide the greatest level of detail.
And when using an online database, an identifier such as Numista’s N# can be useful for locating the exact database entry.
Quick Reference
| Reference | Common Format | Primarily Used For |
|---|---|---|
| Standard Catalog of World Paper Money | P# / Pick | World banknotes, especially established and older issues |
| The Banknote Book | B# | World banknotes, including current issues and detailed varieties |
| The Banknote Book on Numista | TBB# | Numista’s reference label for The Banknote Book |
| Numista | N# | Unique identifier for an individual Numista database entry |
| Friedberg | Fr# | United States paper money |
| Specialized catalogs | Varies | Country-, issuer-, or series-specific collecting |
| Colnect | Database references | Online identification and collection management |
Catalog Numbers Are References, Not Official Banknote Numbers
Perhaps the most important thing to remember is that a catalog number is a reference assigned by a particular publication or database. It generally is not an identification number officially assigned to the banknote by the issuing central bank.
That distinction has become increasingly important as the references used by collectors evolve.
Pick numbers dominated world-banknote collecting for decades and remain deeply embedded in the hobby. Their usefulness did not disappear when publication of the Standard Catalog of World Paper Money ended.
At the same time, collectors need actively maintained references capable of documenting the banknotes being issued today. The Banknote Book increasingly serves that purpose, while online databases such as Numista and Colnect make it easier to research individual notes, compare references, and identify varieties.
Rather than asking which catalog number is the one “correct” number, it is often better to ask:
Which reference most clearly identifies this particular banknote?
Sometimes the answer is Pick. Sometimes it is The Banknote Book, Friedberg, or a specialized catalog.
And quite often, the most useful identification includes more than one.
