If you've ever submitted documents to a government agency, court, or large institution, you may have been asked for a PDF/A file. Most people have no idea what that means - and if you send a regular PDF, it often gets rejected.
PDF/A is a specific subset of the PDF format designed for long-term archiving. This guide explains what it is, how it differs from a standard PDF, and when you need to use it.
What Is PDF/A?
PDF/A ("A" for Archive) is an ISO-standardised version of PDF designed to ensure documents can be reliably reproduced decades into the future. The standard is defined in ISO 19005.
The core idea: a PDF/A file must be completely self-contained. Everything needed to render the document exactly as it looks today must be embedded inside the file - fonts, colour profiles, and all visual information. Nothing can depend on external resources, live links, or software-specific features that might not exist in 20 years.
What Makes PDF/A Different from Regular PDF?
A standard PDF can contain features that make archiving unreliable:
| Feature | Regular PDF | PDF/A | |---|---|---| | Fonts | Can reference system fonts | Must embed all fonts | | Encryption | Allowed | Not permitted | | JavaScript | Allowed | Not permitted | | External content | Allowed (video, links) | Not permitted | | Transparency | Allowed | Restricted (varies by level) | | Colour profiles | Optional | Required (ICC profile embedded) | | Metadata | Optional | Required (XMP format) |
PDF/A strips out or restricts these features so the document is fully self-describing and renderable by any conforming viewer, forever.
PDF/A Versions: 1a, 1b, 2a, 2b, 2u, 3a, 3b, 3u
There are several PDF/A conformance levels:
PDF/A-1 (most common for compliance)
- 1a (Level A): Full accessibility - tagged structure, language specified, all text searchable
- 1b (Level B): Visual reproducibility only - guarantees it looks the same, not that it's accessible
PDF/A-2 (adds features from PDF 1.7)
- Supports JPEG 2000 compression, layers, attachments within the PDF/A container
PDF/A-3
- Same as 2 but allows embedding of any file type (XML, spreadsheets, etc.) inside the archive
For most purposes - legal filings, government submissions, corporate records - PDF/A-1b or PDF/A-2b is the right choice. Check your institution's requirements.
When Are You Required to Use PDF/A?
PDF/A is mandated or strongly recommended in many contexts:
Government and legal filings
- US federal courts (PACER/CM-ECF): some jurisdictions require PDF/A-1
- EU institutions: European Commission requires PDF/A for official documents
- Many national archives mandate PDF/A for records management
Healthcare
- Long-term patient records that must be readable for decades
- DICOM-adjacent workflows where imaging documentation must be archived
Finance and audit
- Annual reports, financial statements required for long-term regulatory retention
- Some auditing standards recommend PDF/A for records subject to 7+ year retention rules
Education and research
- Thesis and dissertation submissions - many universities require PDF/A
- Academic publishers increasingly specify PDF/A for supplementary materials
Corporate records management
- ISO 15489 (Records Management) recommends PDF/A for permanent records
- If your company has a document retention policy, PDF/A is typically specified for permanent records
How to Convert a PDF to PDF/A
Converting an existing PDF to PDF/A is straightforward with SupaPDF:
- Go to SupaPDF PDF to PDF/A
- Upload your PDF file
- Select your conformance level (PDF/A-1b is the default and most widely accepted)
- Click Convert
- Download the PDF/A compliant file
SupaPDF's converter:
- Embeds all fonts used in the document
- Adds a required ICC colour profile
- Strips JavaScript, encryption, and unsupported transparency
- Embeds XMP metadata (required by the standard)
- Validates the output against the ISO specification
Can Any PDF Be Converted to PDF/A?
Most can, but some PDFs have issues that prevent full compliance:
- Encrypted PDFs: PDF/A does not allow encryption. You must remove password protection (Unlock PDF) before converting.
- Transparency effects: Complex transparency in Adobe Illustrator or InDesign-generated PDFs may be flattened (converted to opaque elements).
- Embedded video or audio: These are stripped - PDF/A does not support multimedia.
- External hyperlinks: Live web links are allowed in PDF/A (they're preserved as annotations), but links to external files that no longer exist will be preserved as non-functional links.
How to Verify PDF/A Compliance
After converting, you can verify the file is compliant:
- Open the PDF in Adobe Acrobat - it shows a blue bar at the top confirming PDF/A mode
- Use a free online validator (VeraPDF is the reference implementation)
- SupaPDF's converter validates during export and will flag non-convertible elements
PDF/A vs PDF/X vs PDF/E
- PDF/X - for print production (graphics industry). Ensures colour accuracy for offset printing.
- PDF/E - for engineering documents (CAD drawings, technical documentation).
- PDF/A - for archiving. The one most users encounter.
Frequently Asked Questions
Does converting to PDF/A change how the document looks? In most cases, no. Visual appearance is preserved. The only changes you might notice are removal of transparency effects (which can alter shadows or blends) and embedded fonts replacing system-rendered text (which occasionally causes minor spacing differences).
Can I edit a PDF/A file? Most PDF editors will warn you when opening a PDF/A file and offer to disable archiving mode (which removes the PDF/A conformance). Once you edit and save a PDF/A, it is generally no longer PDF/A compliant. You would need to reconvert after editing.
Is a PDF/A file larger than a regular PDF? Usually slightly larger, because all fonts must be fully embedded. For most documents the difference is under 10%. If the original PDF was already missing embedded fonts, the size increase can be more significant.
What's the difference between PDF/A-1a and PDF/A-1b? 1b (Level B) only guarantees visual reproducibility - it looks the same. 1a (Level A) additionally requires the document to be properly tagged for accessibility (logical reading order, alt text on images, language specified). 1b is sufficient for most archiving purposes; 1a is required when accessibility compliance also matters.
Related Tools
- PDF to PDF/A - Convert any PDF to archival PDF/A format
- Compress PDF - Reduce file size before archiving
- Protect PDF - Add passwords (note: remove before converting to PDF/A)
- Unlock PDF - Remove encryption before PDF/A conversion