PDF/A shows up in document settings, export dialogs, and compliance checklists — often without much explanation of what it actually is or why it exists. If you've ever been told to submit documents in PDF/A format and had no idea what that meant, or if you've seen the option in your software and wondered whether to use it, this is the explanation.
What PDF/A Actually Is
PDF/A is a version of the PDF format specifically designed for long-term archiving. The "A" stands for Archive. It's an ISO standard (ISO 19005) that defines a restricted subset of PDF features — the goal being that a PDF/A file will be readable, accurately, by any compliant viewer, on any system, at any point in the future.
Regular PDFs can depend on external resources — fonts hosted elsewhere, content pulled from the internet, JavaScript that runs on open, encryption that requires a key the viewer may not have. PDF/A eliminates all of this. Everything the document needs to render correctly must be embedded in the file itself, and nothing is allowed that could make the file dependent on external systems or software versions.
What PDF/A Doesn't Allow
The restrictions in PDF/A are what make it suitable for archiving. Compared to a standard PDF, PDF/A prohibits:
- Encryption and password protection — an archived document must be accessible without credentials
- External content references — everything must be self-contained
- JavaScript and executable code — nothing that runs or behaves differently depending on the environment
- Audio and video content — media that depends on codecs which may not exist in twenty years
- Fonts that aren't fully embedded — if the font isn't in the file, it's not in the archive
The tradeoff is that PDF/A files tend to be larger than equivalent standard PDFs, because everything that was previously optional (like full font embedding) is now mandatory.
PDF/A-1, PDF/A-2, PDF/A-3: What's the Difference?
There are three main versions of the standard, each building on the previous one:
- PDF/A-1 is the strictest. Based on PDF 1.4, it prohibits transparency effects and has the most restrictions. Use it when maximum compatibility with older systems is required.
- PDF/A-2 allows transparency, JPEG 2000 compression, and digital signatures. It's the most commonly used version for modern archiving.
- PDF/A-3 adds the ability to embed any file type as an attachment — useful for including source data alongside the presentation document. Used in specialized contexts like e-invoicing standards.
Within each version there are also conformance levels (A and B, sometimes U) that specify how strictly metadata and tagging requirements are followed. For most purposes, PDF/A-2b (level B conformance) is a reasonable default if your software offers the choice.
Who Actually Needs PDF/A
PDF/A is required or strongly recommended in specific contexts:
- Government and public sector records — many national archives and government agencies mandate PDF/A for official document submission and long-term records storage
- Legal and court filings — some jurisdictions require PDF/A for documents submitted to courts or regulatory bodies
- Healthcare records — patient records maintained for long periods often use PDF/A to ensure future readability
- Financial and compliance documentation — regulated industries with long document retention requirements use PDF/A to ensure records remain accessible
Do You Actually Need It?
For most everyday business use — contracts, reports, proposals, invoices — a standard PDF is completely sufficient. PDF/A adds file size and restrictions (no encryption, no interactive elements) that create unnecessary tradeoffs for documents that aren't being maintained for decades.
Use PDF/A when:
- You're explicitly required to by a submission system, government portal, or compliance framework
- The document needs to be reliably readable 20+ years from now without depending on any current software
- You're building a formal records management system for an organization with long retention obligations
Skip it when the document is for immediate use, will be shared and then discarded, or needs features PDF/A prohibits — like password protection or embedded media. For converting documents to standard PDF for everyday sharing, WukongPDF's Word to PDF tool at www.wukongpdf.com handles it without the overhead of archival-format requirements.