Bates numbering is the practice of stamping a unique, sequential identifier onto every page of a document collection so any single page can be located and cited without ambiguity. The name comes from the Bates Manufacturing Company, whose mechanical numbering stamps were standard law-office equipment in the early 1900s; the same sequencing principle now runs as software. A modern identifier usually combines a short party or matter prefix with a zero-padded number, and sometimes a confidentiality designation, applied continuously across every file in a production rather than restarting per document. Litigation depends on that uniqueness: once a page is produced as ABC-000042, every motion, deposition and expert report in the matter can refer to it by that identifier and mean the same page. The practice extends beyond litigation to any workflow, such as regulatory filings, audits and medical records, where a fixed page-level reference must survive copying and reorganisation.
This guide explains legal Bates workflows. BatesFast applies the identifiers; it does not replace review, redaction, or production validation.
Who Decides the Format in a Given Matter?
The parties do, usually in an ESI protocol or a protective order agreed before the first production. That document fixes the prefix, the digit width, whether endorsements are burned onto the page, and how natives are handled where there is no image to stamp.
Courts rarely dictate a format, but some have local rules touching on it, and a judge will enforce whatever the parties agreed. That makes the protocol the operative authority in practice, which is why disagreements about identifiers are usually disagreements about what was written into it.
Because the format binds every later volume, it is worth settling in more detail than feels necessary at the outset. A protocol that specifies the identifier but says nothing about confidentiality endorsements or load-file fields tends to produce an argument at delivery rather than at negotiation.
What Does Bates Numbering Actually Do?
A Bates number solves a narrow but important problem: in a case with thousands of pages spread across hundreds of separate files, how does anyone refer to "that one page" without confusion? A page number alone will not work, because dozens of different documents in the same case can each have their own page 1, page 2, and so on.
A Bates number is unique across the entire production, not just within one document. That means a single alphanumeric string, such as SMITH-004512, points to exactly one physical page in the case, no matter how many thousands of other pages exist alongside it. Attorneys, paralegals, and courts can cite that string in a deposition, a brief, or an exhibit list and everyone involved can retrieve the identical page.
| Property | Ordinary page number | Bates number |
|---|---|---|
| Scope | Restarts at 1 for each document | Continuous across the whole production |
| Format | Plain digits (1, 2, 3…) | Prefix + zero-padded digits (SMITH-000001) |
| Applied by | Word processor or original author | Litigation-support staff or stamping software |
| Purpose | Orientation within one document | Unique retrieval across the entire case |
| Reuse across files | Common (every file has a "page 3") | Never; each number appears exactly once |
Anatomy of a Bates-Stamped Page
A typical Bates number has three optional parts wrapped around a required numeric core: a prefix that identifies the producing party or matter, a zero-padded sequence number, and an optional suffix that flags special handling such as confidentiality. The figure below breaks down a sample stamp.
What Happens to Identifiers After Production?
They become fixed. Once a volume is served, every party cites those pages by their identifiers, and changing one means notifying the other side and issuing a formal correction rather than quietly reissuing the file.
This is why supplemental productions continue the sequence rather than restarting it. A later volume from the same party begins at the next unused number, so an identifier remains unique across the whole matter and a citation written today still resolves years later.
Documents received from another party keep the identifiers they arrived with. Applying your own numbering on top creates two competing references for the same page, and any filing that cites the second one is effectively citing a document nobody else can locate.
Why Bates Numbering Still Matters Today
Modern e-discovery generates far more pages than any mechanical stamp era ever handled, which makes a reliable, gap-free numbering scheme more important, not less. Courts, opposing counsel, and expert witnesses all rely on the same citation working the same way every time: "See SMITH-004512" should retrieve one exact page whether the reader is a first-year associate or a federal judge.
“A missing number is itself evidence that a page was withheld, misfiled, or produced out of order.”
Litigation-support numbering convention
Bates numbering also creates an audit trail. Because the sequence has no gaps, a missing number is itself evidence that a page was withheld, misfiled, or produced out of order, which matters when a production is later challenged. That property is difficult to replicate with any numbering scheme that resets per document, which is exactly why the century-old convention has outlived the machine that named it.
How Do Identifiers Behave in a Review Platform?
Review platforms usually hold two references at once: the identifier stamped on the produced image, and an internal control number the platform assigns for its own tracking. The stamped identifier is the one that appears in filings; the control number rarely leaves the platform.
Families complicate this. A parent message and its attachments are normally kept in one continuous range so the relationship survives, and the platform records the beginning and ending identifier for each document alongside the attachment range that links them.
Native files are handled by reference rather than by stamping. Because there is no page image to mark, the identifier travels in the file name and the load file, commonly with a placeholder image carrying the beginning identifier so a reviewer working from images can still see that the document exists.
Common questions
Who invented the Bates stamp?
The Bates Manufacturing Company, an office-equipment maker active from the late 1800s, produced the self-inking mechanical numbering machines that gave the practice its name. The company's stamps were marketed for banks, insurers, and law offices that needed to number documents in sequence.
Is a "Bates number" the same thing as a "Bates stamp"?
They describe two sides of the same act. The "stamp" is the mark applied to the page (whether mechanical ink or a digital overlay); the "number" is the unique identifier that mark contains, such as SMITH-000142.
Do Bates numbers need to run without any gaps?
Within a single production run, yes: a continuous, gap-free sequence is the entire point, since a missing number signals a missing page. Separate productions can each start their own sequence or continue an existing one, by agreement of the parties.
Can two different pages ever share the same Bates number?
No. A duplicate Bates number defeats the purpose of the system, since it would make a single citation ambiguous. Numbering software and litigation-support staff both treat a repeated number as a production error requiring correction.
What happens if two productions reuse the same prefix?
The identifiers stop being unique, which defeats the purpose. Two pages can then answer to the same citation, and there is no way to tell from the number alone which production a page came from. Prefixes are normally fixed per producing party in the ESI protocol precisely so a later volume cannot collide with an earlier one.
Is Bates numbering used outside litigation?
Yes. Any workflow that needs a fixed page-level reference to survive copying and reorganisation uses the same idea, including regulatory filings, audits, medical records and corporate investigations. The legal context is where it is most formalised, not the only place it is useful.
Further reading: Bates numbering — Wikipedia.