Workflow 9 min read 22 October 2026

PDF Bates Numbering: How It Works, Legal Requirements, and Automation Tools

Bates numbering is the legal standard for stamping a unique sequential identifier on every page of a document production. This guide explains the format conventions, CM/ECF court filing requirements, how to apply Bates stamps with Acrobat and open-source tools, and how to handle multi-document productions.

Bates numbering is the practice of stamping every page of a document production with a unique sequential identifier, named after Edwin Bates who patented the original mechanical Bates stamp in 1891. In legal practice, Bates numbers are the universal reference system for documents: depositions, court filings, and discovery productions all reference documents by their Bates range (e.g., "see ACME-001234 through ACME-001267"). Modern Bates numbering uses PDF software rather than physical stamps, but the principle is identical: every page gets a permanent visible identifier — typically a prefix identifying the producing party plus a zero-padded sequential number. This guide covers the format conventions, court filing requirements, tools for applying Bates stamps, and how to handle multi-document productions.

Bates numbering conventions and formats

There are no universal Bates numbering standards, but conventions are well-established across legal practice: Prefix — Identifies the producing party, typically 3–6 uppercase letters (e.g., ACME, PLT for Plaintiff, DEF for Defendant, SMITH, JONES). In complex litigation with multiple parties, unique prefixes per party prevent numbering collisions. Sequential number — Zero-padded to allow room for expansion. For a production of up to 100,000 pages, 6-digit padding is standard (ACME-000001). For productions of potentially millions of pages, 7 or 8 digits may be used. The padding must be chosen before the production begins — changing it mid-production creates confusion. Separator — Hyphen (ACME-000001) or underscore (ACME_000001) are both common. Some parties use no separator (ACME000001). Choose consistently and specify it in the ESI protocol. Placement — Typically in the lower right corner of each page (least intrusive to document content) or the lower left. Some courts or case protocols specify placement and font. The stamp should not obscure document content. Font — A consistent, legible font at a small size (8–10pt). Courier New or Arial are common. The stamped text should be distinguishable from document content — some firms use a contrasting colour. ESI protocol reference — In e-discovery, the Electronically Stored Information (ESI) protocol agreed between parties specifies the Bates format. Agreeing on a format before production begins is essential.

CM/ECF and PACER court filing requirements

Federal courts in the United States use the CM/ECF (Case Management/Electronic Case Filing) system, accessible via PACER, for document filing. CM/ECF has specific PDF requirements that interact with Bates numbering: File size limits — CM/ECF caps single-file uploads at 25 MB (some courts have lower limits). Large document productions must be split into multiple PDFs. The Bates numbering system must span across split files with consistent continuation. Page limits — Many courts have standing orders limiting brief page counts, which Bates numbers make easy to verify. Exhibit numbering — Exhibits filed with motions in CM/ECF should reference the document's Bates range in the exhibit label. The exhibit list submitted with the filing should show the Bates range for each exhibit. Native file production alongside PDF — FRCP Rule 34 and most ESI protocols require producing documents in native format unless conversion to PDF is agreed. When PDFs are produced, the Bates number on the PDF must match the corresponding entry in the metadata load file. Load files — E-discovery document productions always include a load file (Concordance DAT format, CSV, or XML) that maps Bates numbers to metadata (custodian, date, original file path, document type). The Bates number is the join key between the PDF files and the metadata. See PDFs for Lawyers for e-discovery workflow details.

Applying Bates stamps: tools and automation

Adobe Acrobat Pro — The industry standard for legal PDF work. Acrobat Pro's Bates Numbering tool (Tools > Edit PDF > Bates Numbering) applies headers/footers with auto-incrementing numbers across multiple files. It handles prefix configuration, padding, font, colour, and placement. It can process a list of files and maintain numbering continuity across the entire list. qpdf (command-line) — qpdf can overlay headers/footers on PDFs, though Bates numbering requires scripting around qpdf's capabilities. For large automated productions, Python + qpdf (via subprocess) or Python + PyMuPDF can generate Bates-stamped PDFs programmatically. PyMuPDF (Python) — The fitz library's page.insert_text() and page.add_freetext_annot() methods can place Bates stamps on pages in a Python script. Fully automatable and batchable. Relativity, Concordance, and e-discovery platforms — Major e-discovery review platforms (Relativity, Nuix, DISCO) apply Bates numbers during document production as part of the production workflow. The numbers are applied to the PDFs at export time, and the production load file is generated simultaneously. Important: Once Bates numbers are applied and a document is produced, they are permanent. Never re-number a produced document — re-numbering creates a conflict with all prior references in the record and may constitute a discovery violation. If a numbering error is discovered after production, address it through a production amendment notice, not re-numbering.

Frequently asked questions

Are Bates numbers required by law or court rule?

Bates numbers are not mandated by statute, but they are required by most federal court local rules for document productions, and by most ESI protocols agreed in civil litigation. Federal courts typically require that produced documents be Bates-stamped for reference in filings. Failure to Bates-stamp can result in motions to compel or sanctions for discovery non-compliance. In practice, any multi-document production in US federal civil litigation is expected to have Bates numbers — deviating requires advance agreement from all parties. State court requirements vary; many state courts follow similar practices. Criminal discovery productions typically require Bates numbering as well.

Can I apply Bates numbers without permanently modifying the original PDF?

Bates numbers are typically applied as a header/footer overlay or as a FreeText annotation, either of which modifies the PDF. For legal productions, the Bates-stamped PDF is considered the official production version, and the original file is preserved separately. If the original native file must be preserved unmodified (for hash verification of authenticity), the standard practice is: keep the native file, generate a Bates-stamped PDF copy for production, and record both the native file hash and the Bates-stamped PDF in the production metadata. Many e-discovery platforms handle this automatically, maintaining the native file separately from the produced PDF.

What is the difference between Bates numbering and page numbering?

Page numbers are document-internal — "Page 3 of 12" refers to the position within one document. Bates numbers are production-wide sequential identifiers — "ACME-000342" refers to a specific page within an entire production of potentially millions of pages. A single page might be Page 3 of a 12-page contract, but Bates-stamped as ACME-000342 within a production of 50,000 pages. The distinction is important for legal references: citing "Exhibit 14, page 3" is ambiguous if Exhibit 14 is re-paginated in a different production. Citing "ACME-000342" is unambiguous across all versions and productions. Bates numbers do not replace document page numbers — they coexist on the same page.

Try it yourself

Everything in this article can be done directly in the free PDFTheGuide editor — no account required.

Edit PDF Annotate PDF Open editor