Accession Numbering
Configure how your archive numbers what it takes in, and how it numbers what it catalogues. Navigate to Settings → Numbering. Anyone can look; only organisation admins can change anything — everyone else sees "Only organisation admins can change the format."
Nothing on this page changes a number something already has.
Numbering formats
Archivers.ai supports two standard accession numbering approaches:
Yearly with year prefix (resets each year)
Numbers restart at 001 each calendar year, with the year as a prefix:
2026/001,2026/002, ...,2026/150- Then on 1 January 2027:
2027/001,2027/002, ...
This is the default format and aligns with most UK archives' practice. Accessions remain sortable by year, and you avoid four-digit accession numbers.
Sequential — no year prefix (continuous)
Numbers increment forever, never resetting:
ACC-001,ACC-002, ...,ACC-999,ACC-1000, ...
Use this if your organisation prefers a single continuous sequence or if you're back-cataloguing material from multiple years and want a unified numbering scheme.
Configuring your format
The Accession numbers section has a Current settings card with five controls:
| Control | What it does |
|---|---|
| Repository prefix (optional) | Up to 20 characters — e.g. NA for Nottinghamshire Archives. Leave blank for none |
| Year format | Four-digit (2026) or Two-digit (26) |
| Separator | /, -, . or : |
| Number padding (digits) | 1 to 8 — 3 gives 001, 4 gives 0001 |
| Numbering style | Yearly with year prefix (resets each year) or Sequential — no year prefix (continuous) |
A Preview below shows the shape you've built, together with the next available number. Click Save format when it looks right.
Changes apply immediately to new accessions. Existing accessions keep their assigned numbers.
Auto-filling vs manual numbers
When creating a new accession, the platform pre-fills the next number in sequence. You can:
- Accept the suggested number — click Next and the number is assigned. The counter advances.
- Edit or clear it — useful for back-cataloguing or when you're assigning numbers from a different system. Manual numbers don't advance the counter.
If you accidentally skip a number, use the Starting number control (see below) to reset the sequence.
Starting number
The Starting number card sets the next number the system will suggest. Type it into Next number and click Update next number. The card tells you which counter it applies to — the current year's, or the continuous one.
This is mainly for migration: if your last accession in the old system was 2026/045, set the next number to 46 and auto-numbering picks up from there.
Setting the next number only affects future accessions. Set it lower than a number already used and the next accession will clash with it, and the save will be refused.
Which numbers are used
Below that, a card reports the range of numbers used this year and names any gaps — "3 numbers in between are not on any accession — usually because somebody typed a number by hand, or an accession was deleted." Numbers written in a shape the page can't count are reported separately; they're on their accessions and nothing is wrong with them.
Numbers held back
You can reserve a number before the material arrives, or record one as never used.
- Hold a number — enter the Number and, optionally, What for? (e.g. the Smith deposit, arriving next week). A held-back number won't be given out automatically.
- Mark a number as never used — for a number that will never belong to an accession. It stays in the list so nobody wonders where it went.
- Give it back — releases a held number into the sequence again.
Empty, the card reads "No numbers are being held back." A number that is already on an accession can't be held back.
Duplicate numbers
Accession numbers must be unique within your organisation. Enter one that's already taken and the save is refused, naming the accession that has it: Accession number "2026/012" is already in use by "Smith family papers".
Back-cataloguing
When entering historical accessions with existing numbers from a legacy system:
- Create the accession normally
- On Step 1, clear the auto-filled number and type your legacy number (e.g.
1987/042) - Continue through the wizard
The counter won't advance — manual numbers are treated as overrides. This lets you integrate legacy numbering without gaps in your new automated sequence.
Export formats
Accession numbers appear in every export format:
- EAD3 XML — in the
<unitid>element - Dublin Core — as
dc:identifier - CSV exports — dedicated
accession_numbercolumn - BagIt — in the
bag-info.txtmanifest
Catalogue references
The second half of the page, Catalogue references, governs the reference a collection or a record is catalogued under — a separate setting from accession numbers, and again admin-only.
- Sharing a reference — normally a reference that something else in the same place already has is refused, naming the other record, with the choice to save anyway. Tick the box and it is never refused. Either way, shared references appear on the Reports page.
- Catalogue numbers — choose what separates the parts (
/,-,.or a space, so a record insideDD/1is numberedDD/1/1), how numbers are written (plain, or padded to 3, 4, 5 or 6 digits) and whether the next number carries on from the highest or fills the first gap. Carrying on from the highest never gives out a number something else once had. A preview updates as you choose. - Your archive's code — your country and the code your service is known by nationally (Nottinghamshire Archives is 0157). Used when a reference is written out in full, and in the finding aids you send to other services.
- Earlier years — how far numbering had got at the end of each year, once there's more than one year to show.
Your existing references are never changed by anything on this page.
Questions?
If you're unsure which format to use, "Yearly with year prefix" is the safe default — it's the most common approach in UK and Commonwealth archives.