How to catalogue a coin collection: a practical guide
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A good collection catalogue is more than tidiness. It is proof of ownership, the basis for valuation, an aid when you sell, and protection in case of theft or fire. Below is a guide to how to go about it, from dividing your holdings into collections, through description and photography, to backups.
1. Divide your holdings into collections
Start with a general division: by country, period, ruler or theme (for example “Interwar Poland”, “Piast denars”, “World gold coins”). One coin can belong to only one collection, so choose the criterion that best matches how you collect. Coins you do not own yet but are looking for are best kept separately, as a wanted list.
2. Assign numbers and record the basic data
Every coin needs its own inventory number, even if you have several identical specimens. Record at least what lets you identify it:
| Field | What it is for |
|---|---|
| Country, denomination, year | basic identification |
| Ruler, mint, mint mark | telling varieties apart |
| Metal and fineness | bullion value, distinguishing similar types |
| Weight and diameter | verifying authenticity and variety |
| Grade | one of the main factors of price (grading scales) |
| Catalogue numbers | pinpointing the variety (catalogues) |
3. Weigh and measure
Give the weight to 0.01 g (a jeweller’s scale) and the diameter in millimetres to 0.1 mm (calipers). These two parameters help you tell varieties apart and detect fakes, and catalogues give them almost without exception. Record the actual measurements and, if a catalogue gives reference values, keep them in a separate field.
4. Photograph every coin
- Take separate photos of the obverse and the reverse, and for an interesting edge also a photo of the side.
- Use bright, diffused light (by a window or from two sides) and no flash, which creates glare.
- Choose a uniform dark or grey background and shoot straight from above.
- Include a ruler or another scale if the photos are also to be used for comparisons.
- Keep the originals in high resolution. You can make smaller copies from them for printouts and listings.
Photos are evidence of the condition a coin was in, and the most important document for insurance or a dispute with a seller.
5. Record the provenance and the price
Note who you bought the coin from and when, for how much, and, if it comes from an auction, the lot number and the auction house. Such a history (provenance) raises the credibility of a specimen and can be valuable when you sell. Also record successive valuations with a date and a source (a catalogue, an auction, your own estimate) so that you can see how the value of your holdings changes.
6. Note where each coin is kept
Describe the storage place precisely enough that you can find the coin a year later: for example “home safe › drawer 2 › album › page 4 › slot 3”. That way you do not search the whole collection, and during an inventory you know what to look for. For how to store coins, read How to store coins.
7. Back up your catalogue
A catalogue is worth as much as its last backup. A good practice is the 3-2-1 rule: three copies of your data, on two different media, one of them off-site. In NumiStack you can download a full backup (JSON), a coin list (CSV) and PDF reports, and the same JSON file is used to restore your data. Keep the backup away from the photos and from the coins themselves: an inventory stored in the same place as the collection will not help after a theft or a fire.
How to speed up the work
Describing a collection from scratch can be tedious. In NumiStack the AI scanner reads photos of the obverse and reverse and proposes country, year, metal, grade and catalogue number, and you confirm or correct the result; you can also import data from an auction listing. Fields the AI is unsure about are flagged and nothing is saved automatically. Always check the suggestions, especially the grade and the catalogue numbers.