Concepts

PDF vs PDF/A: what the difference is and when it matters

PDF/A is PDF with the rules tightened for long-term archiving. What it forbids, when you are actually required to use it, and how to tell what you have.

By The Editorial Team · Reviewed by Engineering · Published 2026-08-03

Someone asks you to submit a document “as PDF/A” and it sounds like a different file format. It is not. PDF/A is ordinary PDF with a set of restrictions applied, designed so the file will still render the same way decades from now.

What PDF/A forbids

The rules all serve one goal: the file must be self-contained and deterministic. Nothing may depend on software, fonts, or resources that might not exist in the future.

  • Fonts must be embedded — no relying on whatever the reader happens to have installed.
  • No JavaScript, no launch actions, no embedded executables.
  • No encryption or passwords.
  • No audio or video content.
  • Colour must be described unambiguously, usually with an embedded colour profile.
  • Metadata must be present in XMP form and follow the standard.

The variants

PDF/A-1 is the strictest and oldest; PDF/A-2 and PDF/A-3 relax parts of it and add features (PDF/A-3 notably allows arbitrary attached files). Each has conformance levels — “b” for basic visual reproduction, “a” for that plus a tagged structure that assistive technology can read. If someone specifies a level, they usually mean PDF/A-1b or PDF/A-2b.

When you actually need it

Court and government filings, academic thesis deposits, records with a legal retention period, and formal tender submissions are the common cases. For everyday sharing, a normal PDF is fine and PDF/A only makes the file larger — embedding every font is not free.

How to tell what you have

A PDF/A file declares its conformance in its XMP metadata, and most readers show a banner when they open one. Note the consequence for the tools here: because the declaration lives in metadata, running Remove PDF Metadata on a PDF/A file strips that declaration, so the file stops claiming conformance.

We do not convert to PDF/A — doing it properly means embedding fonts and colour profiles and then validating the result, and a converter that skips the validation is worse than no converter. Use the export option in the application that produced the document.

The practical route

Most word processors and layout tools offer “Save as PDF/A” or an equivalent export setting — that is the reliable path, because the original application still has the fonts and colour information. If you only have the finished PDF, a dedicated validator will at least tell you whether it already conforms.

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