When someone says documents have been Bates stamped, they mean every page has been marked with a unique, sequential identifier so each one has a permanent address inside the larger set. The label usually sits in the lower-right corner of the page and combines a short prefix with a zero-padded number, like SMI_0001 or ACME000001. Once a page carries that number, it keeps it for the life of the case or collection, and anyone can refer to that exact page without ambiguity.
The practice is named for Edwin G. Bates, who patented an automatic numbering machine in the late 1800s. More than a century later, it is still the standard way to organize large document sets in litigation and in any field where page-level tracking matters.
What a Bates Number Looks Like
The simplest form is a zero-padded number such as 000001, with each following page incrementing by one. Six digits is the usual default, producing a range from 000001 through 999999, though longer sequences are common in large productions.
Most productions add a prefix or suffix so one party’s documents can be told apart from another’s. A plaintiff named Smith might produce pages labeled SMI_0001; a corporate defendant might use ACME000001. The prefix identifies the source and the sequential portion keeps the pages in order. Once a number is assigned, it stays put. If the page is pulled out and mixed into another stack, the Bates number still tells you exactly where it belongs.
Why Documents Get Bates Stamped
The point is to make every page findable and verifiable. In a collection of tens of thousands of pages, saying “turn to the third page of the second exhibit” collapses the moment two people have their exhibits in different order. Saying “turn to SMI_004372” puts everyone on the same page instantly.
Bates numbers also create a tamper-evident record. If a production originally ran from 000001 through 005000, a page later slipped in or quietly removed shows up as a gap or a duplicate in the sequence. Courts and opposing counsel treat the numbering as a kind of chain-of-custody tool for both paper and electronic records.
Privilege logs rely on the same system. When a party withholds documents on confidentiality or privilege grounds, the log typically lists the Bates number range of what was held back so opposing counsel can see the scope of the withholding and challenge it if they want to.
Where You’ll See Bates Stamping
Litigation Discovery
Most Bates stamping happens in civil litigation. Federal Rule of Civil Procedure 34 requires a party producing documents to either hand them over as they are kept in the ordinary course of business or organize and label them to match the categories in the production request. The rule does not spell out Bates numbering, but it does require that productions be organized and usable, and Bates stamping has become the default way to satisfy that obligation.
Many local court rules and standing orders go further and require it outright. When parties negotiate a discovery exchange, the stipulation almost always sets out a Bates numbering format. Courts have found that productions delivered without Bates stamps, where prior productions used them or where the format had been agreed upon, fall short of Rule 34. In one federal case, the producing party’s attorneys were sanctioned and ordered to pay the opposing side’s processing costs after delivering unstamped documents the court deemed not reasonably usable.
Confidentiality Designations
When a case involves trade secrets, proprietary business information, or sensitive personal data, the parties typically negotiate a protective order that governs how confidential material is handled. The confidentiality designation often rides on the same line as the Bates number. A page might read ACME000472 — CONFIDENTIAL or ACME000472 — HIGHLY CONFIDENTIAL — ATTORNEYS’ EYES ONLY, depending on the restriction level.
Protective orders usually require the producing party to label every page that contains protected material. If only part of a page qualifies, the party has to mark the protected portions specifically, often with margin notations or highlighting. Anyone handling the page can see the restrictions by glancing at the Bates line.
Native Files and Non-Document Evidence
Traditional Bates stamping prints a number on each page. That approach does not fit files without conventional pages: spreadsheets, emails, audio recordings, video files, and databases. These are called native files in litigation, and they are handled differently.
Each native file gets a single Bates number rather than one per page, and the number is applied as the file name instead of being stamped onto the content. A Word document might be renamed SMI_0004500.docx and a video file SMI_0004501.mp4. A load file or index then cross-references each Bates number with metadata like the original file name, creation date, and custodian. If the native file later needs to serve as a trial exhibit or get referenced at a deposition, it is often converted to PDF or TIFF images at that stage and given page-level Bates numbers.
How Bates Stamping Is Done Today
Almost all Bates stamping is now digital. Software such as Adobe Acrobat Pro lets a user select a batch of PDFs, set a starting number, choose a digit length (six is standard), add a prefix or suffix, and apply sequential numbers to every page in a single pass. Thousands of pages can be numbered in minutes.
The original mechanical stamping machines still exist, and some are still manufactured. They are handheld devices with rotating number wheels that advance automatically after each impression. They work fine for small jobs, but no one is hand-stamping a 50,000-page production in 2026. Digital tools handle that kind of volume without the sequencing errors that creep into manual work.
Uses Beyond Litigation
Litigation drives most Bates stamping, but the same principle applies anywhere large document sets need reliable page-level tracking. Medical records departments use sequential numbering to maintain patient file integrity. Financial auditors stamp working papers so every schedule and supporting document can be traced back to a specific audit step. Insurance companies use it when assembling claim files that may later become evidence. Archival projects at libraries and government agencies apply similar numbering to digitized collections so every scanned page maps back to its physical original.
The logic is the same across all of those settings: give every page a unique, permanent address so it cannot be lost, misidentified, or silently removed.