What is Bates numbering on a PDF?

Bates numbering places a unique, sequential identifier on every page of a document set — usually a short prefix, a zero-padded number, and an optional suffix, like ABC-000123. Each page gets its own number, so anyone in a case can point to an exact page and everyone knows which one they mean. It is standard practice in legal discovery, medical records, and regulatory submissions.

Is Bates numbering legally required?

It depends on the court and the case. Some courts require consecutive page numbering on filed documents — the Massachusetts Appeals Court, for example, requires it on every filing including record appendices. In discovery, Bates numbers are usually agreed between the parties rather than ordered by a judge, but once a production is stamped, the numbers become the shared reference for the whole case.

How many digits should a Bates number have?

Six is the common default in Adobe Acrobat, and the range there runs from three to fifteen digits. Six digits covers up to 999,999 pages, which is more than most productions need. The practical rule is to pick a width that fits your largest expected production and keep it fixed — changing digit counts midway breaks the sequence.

Can I add Bates numbers to a PDF for free?

Yes. Free browser tools such as Mapsoft's Bates Numbering tool and Sejda stamp Bates numbers without installing anything: upload the PDF, set the prefix, digit count, and starting number, pick a header or footer position, and download the stamped file. PDF-XChange Editor also offers Bates numbering at a low cost. The trade-off against Acrobat Pro is batch handling — free tools usually stamp one file at a time.

How do I Bates-number several PDFs with one continuous sequence?

Either merge the documents into a single PDF first and stamp that, or stamp the files one at a time, setting each file's starting number to continue where the previous one ended — if the first document ends at ABC-000214, start the second at 215. Acrobat Pro can also stamp across many files in one batch operation.

How to Add Bates Numbers to a PDF (Legal Stamping Guide)

Picture a lawyer handing over 25,000 pages to the other side in a lawsuit. The other side reads one page, finds something important, and writes back: "see page 14,203." Which page is that — the fourteenth thousand page of the third box, or the one in the folder labelled "Emails, March"? Without a shared numbering system, that reference is useless, and in litigation a useless reference can cost a case.

Bates numbering is the fix, and it has been for more than a century. Every page of the production gets a unique stamp — a short prefix, a number, sometimes a suffix — printed in the header or footer. Page 14,203 becomes XYZ014203, and from then on everybody in the room is looking at the same page.

What a Bates number actually looks like

A Bates number has three parts, and only the middle one is compulsory:

Prefix — usually a party or matter code: ABC, DEF, SMITH, or a case number.
Number — zero-padded to a fixed width, so the sequence sorts properly: 000123, not 123.
Suffix — optional, often used for confidentiality tags like "-CONF".

So a full stamp reads something like ABC-000123. The padding matters: without it, a computer sorts page 1000 before page 999. Six digits is the usual default — Adobe Acrobat defaults to six, and its range runs from three to fifteen — which covers up to 999,999 pages. Pick a width that fits your largest expected production and then never change it mid-case.

The name comes from the Bates Automatic Numbering-Machine, a hand stamp patented in the 1890s and made by the Bates Manufacturing Company of New York. Each press advanced its counter, so a clerk could number a stack of paper quickly.

When you actually need it

Bates numbering is not a legal requirement for every PDF. It is a convention, and conventions only bite when the other side — or the court — expects them. The situations where it shows up:

Discovery and document production. When one party hands documents to another, Bates numbers are the agreed reference system. Briefs cite them, depositions cite them, exhibits cite them. E-discovery platforms like Relativity, Everlaw, and DISCO treat Bates numbering as part of the production workflow, tracking sequences across rolling productions and flagging duplicates.
Court filings. Some courts require consecutive page numbering outright. The Massachusetts Appeals Court, for instance, requires all parties filing any document — including a brief or a record appendix — to include consecutive page numbers, and publishes step-by-step Bates instructions for Acrobat.
Medical records and regulatory submissions. Hospitals, insurers, and regulators use the same trick for the same reason: when a file runs to thousands of pages, a unique number per page is the only reliable way to refer to one.

For a ten-page contract, plain page numbers will do. Bates numbering earns its keep once "page 47" stops being a useful address.

Bates numbers are not page numbers

This is the confusion that causes most mistakes. A page number says where a page sits inside one document: page 1 of 40. A Bates number says which page it is inside an entire production, across many documents: ABC-000847 might be page 12 of the fifth file you produced.

That difference drives two practical rules. First, Bates numbers never restart — a new document in the same production continues the sequence. Second, they survive reorganisation: if you reorder the files, the stamp stays with the page it was printed on, which is exactly the point.

Method 1: Adobe Acrobat Pro (the standard route)

Acrobat Pro has Bates numbering built in and handles batches properly. The steps, as documented by the Massachusetts Appeals Court:

Open Acrobat Pro and go to Edit, then More, then Bates Numbering, then Add.
Add your files — individual PDFs, whole folders, or files you already have open. Use the Move Up and Move Down buttons to set the order, because the numbering follows the file order.
Choose your output options: a target folder and naming preferences for the stamped copies.
Click into the header or footer box where the number should go — most firms use the lower-right corner — and select Insert Bates Number.
Set the digit count (six is the default), the starting number, and any prefix or suffix.
Check the preview, then click OK. Acrobat stamps every page across all selected files in sequence. If your pages are already full-bleed, turn on the appearance option to shrink documents slightly so the stamp does not overwrite existing text — a Bates number printed on top of a signature line helps nobody.

Method 2: PDF Expert on Mac and iPad

If your practice runs on Apple hardware, Readdle's PDF Expert is the lighter-weight option. Open the file, go to Edit PDF, then Header and Footer, then Add Bates Numbers. From there you set the digit count, the prefix and suffix, and the starting number — useful when a new document needs to continue a sequence you started last week. Layout and font options control where the number sits and how it looks, and Apply stamps the whole file.

Method 3: free online tools

Not every Bates job justifies a subscription. For a one-off production, a browser tool does the job in minutes: Mapsoft's free Bates Numbering tool (upload, set prefix, digit count, starting number and optional suffix, pick header or footer, download — nothing to install), Sejda (Bates stamping in its free tier, with the usual file-size limits), and PDF-XChange Editor (a low-cost desktop editor with Bates numbering built in).

The honest trade-off: free tools usually stamp one file at a time and offer little batch automation. For a few hundred pages once, that is fine.

Numbering across several files

The most common real-world snag is a production that arrives in pieces. Two ways through it:

Merge first, stamp second. Combine the documents into one PDF, then stamp the merged file. The sequence runs straight through, and there is nothing to track. PDFEdit's free merge tool does the combining in the browser if that is the step you need.

Stamp in order, carry the number forward. If the files must stay separate, stamp the first file, note where its sequence ends, and set the next file's starting number to continue — if the first document ends at ABC-000214, the second starts at 215. Acrobat Pro can do this across many files in one batch; with free tools, you do it file by file and keep a note of the last number used.

Either way, keep a log. A one-line note — "ABC-000001 to ABC-000214: emails; ABC-000215 to ABC-000402: contracts" — is the difference between a clean production and a panicked search for a gap in the sequence.

Mistakes that cause real trouble

Stamping your only copy. Always stamp a copy. The numbers are burned into the pages, and removing them later is a separate, fiddly job. Keep the unstamped originals.
Renumbering mid-production. Once a Bates number has been cited in a letter, a brief, or a deposition, it is permanent. If you discover a gap or a duplicate, fix the log, not the numbers.
Mixing digit widths. Six digits in one production and four in the next breaks sorting and looks careless. Decide once.
Stamping over content. Check the first few pages after stamping, especially pages with full-width tables or signatures at the margins. Use the shrink-to-fit option if your tool offers it.
Confusing Bates numbers with redactions. A Bates stamp identifies a page; it does not hide anything on it. If a page needs material removed, redact it first and stamp the redacted version.

What PDFEdit can do here

A quick note on where our own tools fit, because honesty beats a sales pitch: PDFEdit does not have a dedicated Bates-stamping tool. What it does have is the two steps around it. The add page numbers tool puts plain sequential numbers on a PDF in seconds — right for short documents and personal files, not a substitute for Bates stamps in a legal production. And the merge tool combines several PDFs into one file, which is the first step of the merge-first stamping method above. Both run entirely in your browser, so the file never leaves your device.

The short version

Bates numbering gives every page in a production a unique, citable identity: prefix, zero-padded number, optional suffix. Courts and opposing counsel expect it once a production gets large, and some courts require consecutive numbering on filings outright. Acrobat Pro is the standard tool for batches, PDF Expert covers Apple workflows, and free online tools handle one-off jobs. Merge first or carry the sequence forward across files, stamp copies rather than originals, and write down where each range starts and ends. Do that, and "see page ABC-000847" will always mean exactly one page.