A KM number is a unique identifier assigned to a coin type in the Standard Catalog of World Coins, published by Krause Publications.
KM stands for Krause-Mishler, after Chester L. Krause and Clifford Mishler, who co-authored the catalog’s first edition in 1972.
Each number identifies a specific coin type by country, denomination, and date of issue — giving collectors and dealers a shared shorthand that works across languages and borders.
Instead of describing a coin in full, a collector can simply cite the country, date, denomination, and KM number. Anyone with a copy of the catalog can look it up immediately. KM numbers are listed on major collecting platforms, including Numista and World Coin Gallery
History and Origin
Chester L. Krause founded Krause Publications in 1952 in Iola, Wisconsin, starting with Numismatic News. Two decades later, in 1972, Krause and Clifford Mishler — who had joined the company as a numismatic editor in 1962 — co-authored the first edition of the Standard Catalog of World Coins.
That edition was published by Krause Publications. It was not published by Random House, and it was not related to the Red Book (A Guide Book of United States Coins), which is an entirely separate publication covering US coins only.
From the second edition onward, Colin R. Bruce II took over as the catalog’s chief compiler and editor, a role he held from 1976 through his retirement in 2008.
Despite that editorial evolution, the KM designation stuck — named after the original authors whose initials now identify the system worldwide.
Using authors’ initials as catalog reference codes is standard practice in numismatics. The Y-number system (Yeoman) and C-numbers (Craig) predate KM and follow the same logic. For most world coins, the Krause-Mishler system is the default.
What a KM Number Does?
A KM number identifies a coin type — a specific design issued by a specific country in a specific denomination. It doesn’t indicate whether a coin has been circulated.
Circulation status is a matter of grading (conditions like Fine, Very Fine, or Mint State), determined separately by physical examination.
For example, the Morgan Silver Dollar — struck from 1878 to 1921 — carries the designation KM# 110.
Whether a specific Morgan dollar is circulated or uncirculated, worn or pristine, doesn’t affect its KM number. Every Morgan dollar from that series shares KM# 110 regardless of condition.
Why Collectors Use KM Numbers?
The practical value is consistency. World coins span hundreds of countries, dozens of scripts, and centuries of varying dating systems.
A KM number cuts through that complexity — a collector in Singapore and a dealer in Ohio can reference the same coin without either having to describe it from scratch.
The catalog itself — and by extension the KM number — provides mintage data, metal composition, design details, and market valuations across multiple grades of condition.
That’s what makes it useful for valuation: not the number itself, but the detailed listing the number points to.
Auction houses, online marketplaces, and cataloging databases all rely on KM numbers for exactly this reason. The system reduces ambiguity — particularly for coins from different eras that may look similar but differ in metal content or mintage.
Before you go…
Understanding the KM number and its significance in coin collecting can benefit collectors and dealers alike. By utilizing resources such as online databases and physical books, collectors can easily find the KM number of their coins and make informed decisions about their collections.
Check out my next article: “What is Morgan Dollar Vam Price Guide.”
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