How to read a coin catalogue entry: reference numbers, mintages, issue pages

A coin catalogue is not a shop and not a price list, though sellers borrow its numbers constantly. It is a structured record of what issuers have made — one entry per coin type, written so that two people on opposite sides of the world can be sure they are discussing the same object. Once you can read the fields, "check the catalogue" stops being a brush-off and becomes a ten-minute verification. This walkthrough assumes you have a candidate in hand — the identification guide covers getting to one, and the coin-terms glossary decodes any field label you meet along the way.

What a catalogue entry is

An entry describes a coin type, not an individual coin: the issuer, the denomination, the years the design was struck, and the physical specification — composition, weight, diameter, edge — that a genuine example should match. Community catalogues such as Numista organise the world's coins into exactly this kind of record; their own help pages describe searching it by name, reference number, issuer and physical filters. Institutional collections work the same way at larger scale: the American Numismatic Society, for example, maintains its holdings as catalogued research objects rather than a display of curiosities. Numista: How Can I Search the Catalogue, American Numismatic Society

Mints publish the same information for their own products in a lighter form: The Royal Mint, for instance, keeps a public designs-and-specifications page for the circulating £2 coin, listing each design with its issue details. Issuer pages like this are the canonical check for modern coins — the record came from the maker itself. Royal Mint: Two Pound Coin Designs

Reference numbers and why they matter

Catalogue numbers are names, not grades of quality. The most common are the "KM" numbers from the Standard Catalog of World Coins — a printed reference series whose identifiers appear everywhere in listings — and Numista's own "N#" number, which its help pages describe as a permanent, unique identifier for a type of coin, banknote or exonumia. Deliberately, the N# carries no embedded information: it does not encode country, date or rarity. Its only job is that no two entries share one. Numista: What is the N# number

Where a type was struck across several years, mintmarks or variants, Numista notes that a further "NN#" can label one specific version — its help example gives the Columbian Exposition half dollar one type number, N# 4396, while the 1892 and 1893 strikings carry separate NN# numbers. In practice: a reference number in a listing tells you which record to open; the version lines inside it tell you which row of that record your coin might be. Numista: What is the N# number

Fields to compare: dates, mints, mintage, composition, edge

With a candidate entry open, work the fields in order rather than scanning the pictures. Date first: the entry's year range tells you when the type was struck, and per-year lines narrow it to your coin's actual date. Mint second: entries record where each version was struck, and the mint-mark guide shows where those marks hide on a coin. Mintage third: entries list how many of each version were produced — The Royal Mint's mintage-figures page explains that for circulating UK coins these figures reflect coins minted and released or requested for circulation, which makes the figure a production count, not a survival count. Royal Mint: UK Coin Mintage Figures

Then the physical fields, which are the strongest match or mismatch you have: composition (what metal the issue was struck in), weight and diameter (the numbers your coin should land near — the measuring guide covers how to take them), and the edge, which entries describe as plain, reeded, lettered or fitted with a security feature. Issuer specification pages are unambiguous here: The Royal Mint's £2 page lists edge inscriptions per design, which settles questions a photo never could. Royal Mint: Two Pound Coin Designs

Varieties versus types

A type is a design: the combination of issuer, denomination and artwork an entry describes. Within it sit versions — years, mints, finish editions — and sometimes varieties: deliberate or accidental die differences that collectors track separately, such as an altered edge inscription or a re-cut date. Catalogues handle this by keeping one type record and listing versions inside it, which is why an entry page often shows a table of years rather than a single description.

This is the level where identification gets serious. Two coins can share the type yet differ on a version line in ways collectors care about, so "my coin matches the picture" is the start of the comparison, not the end. The error-and-variety guide covers how deliberate varieties differ from post-mint damage; the point here is that the catalogue's version rows are where those differences live.

When the coin and the catalogue disagree

A mismatch is information, and it has several honest explanations. Most commonly the record is right and the reading was wrong: a worn date misread, a mintmark mistaken for damage, a version row missed. Slightly less commonly the wrong catalogue section is open — a lookalike issue from another country or period, or an object that was never a coin at all — a token or medal, which belongs to a catalogue's exonumia categories or a separate specialist reference rather than the coin listings (the token-medal guide covers that split).

Measurement mismatches deserve care, and no universal allowance settles them. A circulating coin loses some weight to wear, every issue has its own manufacturing tolerance, and a kitchen scale has its own error — so before concluding anything, repeat the measurement, check the equipment and compare against the exact issue's specification. A persistent, unexplained mismatch in weight, diameter or edge description is a different conversation — either a different issue entirely, or something altered or reproduced after the mint, which the counterfeit guide takes up. And finally: catalogue coverage has edges. Community catalogues are living documents that lag new issues, and issuer pages can be silent on older or withdrawn products. "Not in the catalogue" ends an identification attempt; it does not condemn the coin.

Questions people ask

Which catalogue should I start with?

For a first pass, a free searchable online catalogue such as Numista covers world coins and documents its own search workflow. For modern coins, the issuing mint's specification pages are canonical. For older material, the printed Standard Catalog of World Coins — the source of KM numbers — is the conventional reference, often available through libraries.

What does "KM" stand for?

KM numbers are the reference identifiers assigned in the Standard Catalog of World Coins. They appear constantly in dealer listings and auction descriptions for the same reason N# numbers appear in online discussions: a shared number removes ambiguity about which coin is meant.

Is a low mintage figure proof my coin is rare?

A mintage figure is a production count — how many were made — not a count of how many survive, and it says nothing about collector demand. The Royal Mint presents its UK mintage figures as records of circulating coins minted and released; what low numbers mean for any individual coin is a question the value-drivers guide addresses.

The entry shows a value column — can I trust it?

Catalogue price indications are compiled estimates, age quickly, and cannot see your coin's condition. Treat them as context for a conversation, not an appraisal — the value-from-a-photo guide explains why no printed figure settles what a specific coin would sell for.

Does Coin Says Hi give me the catalogue entry?

A possible photo reading names candidates worth looking up — the catalogue check is then yours to run, field by field, against the entry. That division of labour is deliberate: the reading proposes, the record disposes. Try it on your coin.

Sources and scope

Numista's help pages support the account of catalogue search fields — including its exonumia categories for tokens and medals — and the definitions of the N# type identifier and NN# version identifier, including the Columbian half-dollar example; the cited URLs are Numista's own help articles. The Royal Mint's £2 designs page supports the issuer-published specification example, and its mintage-figures page supports the production-count framing for UK circulating coins. The American Numismatic Society's site supports the institutional-catalogue framing. Catalogue conventions differ between publishers, and community catalogues are works in progress — issuer documentation is canonical where it exists. Sources last checked 2026-10-01.

Spotted an error? Tell us — include the page address and what seems wrong.