PDF/A vs PDF — What's the Difference?
5 min read
PDF/A is an ISO-standardised version of the PDF format specifically designed for long-term archiving. The "A" stands for Archive. While a regular PDF can reference external fonts, contain JavaScript, embed video, or use encryption, PDF/A restricts all of these to ensure the document remains fully self-contained and readable decades from now.
Why PDF/A Exists
Standard PDFs can reference external resources — fonts hosted on a server, colour profiles, embedded scripts. If those resources become unavailable in 20 years, the document may not render correctly. A PDF that depends on Arial being installed on the reader's system might display incorrectly on a system that doesn't have it.
PDF/A mandates that everything needed to display the document is embedded inside the file. Fonts, colour profiles, and all content must be self-contained. No external dependencies, no scripts, no encryption that could prevent future access.
PDF vs PDF/A — Side by Side
| Feature | PDF/A | |
|---|---|---|
| Purpose | General use | Long-term archiving |
| External fonts | Allowed (referenced) | Must be embedded |
| Encryption | Allowed | Not allowed |
| JavaScript | Allowed | Not allowed |
| Audio/video | Allowed | Not allowed |
| Transparency | Allowed | PDF/A-1: No. PDF/A-2: Yes |
| Colour profiles | Optional | Required (ICC profile embedded) |
| File size | Smaller | Slightly larger (embedded fonts) |
PDF/A Versions Explained
PDF/A-1 (ISO 19005-1, 2005)
The original standard. Two conformance levels: 1a (full accessibility, tagged structure) and 1b (basic visual appearance). No transparency, no layers. Most widely required by government and legal systems.
PDF/A-2 (ISO 19005-2, 2011)
Adds JPEG 2000 compression, transparency, layers, and digital signatures. Better compression than PDF/A-1. Conformance levels: 2a, 2b, 2u.
PDF/A-3 (ISO 19005-3, 2012)
Allows embedding of arbitrary file formats (e.g., XML, spreadsheets) as attachments. Used in e-invoicing standards like ZUGFeRD.
When You Need PDF/A
- → Legal document submission to courts (many require PDF/A-1b)
- → Government records and public administration filings
- → Academic theses and dissertations (many universities mandate it)
- → Long-term business records — contracts, financial statements
- → Medical records required to be stored for 10–30 years
Convert your PDF to PDF/A now
Free, browser-based conversion to PDF/A archive format. No upload, no account required.
Convert to PDF/A Free →Frequently Asked Questions
Do I need PDF/A for everyday documents?
No. PDF/A is designed for long-term archiving where documents must remain readable for decades. For emails, sharing, and everyday use, a standard PDF is simpler and often smaller.
Can I open a PDF/A file in a normal PDF viewer?
Yes. PDF/A is a subset of the PDF standard, so any PDF viewer can open it. Adobe Acrobat, Preview, Chrome, and other readers all open PDF/A files without issue.
Which PDF/A version should I use?
PDF/A-1b is the most widely accepted and simplest to produce. PDF/A-2b adds support for JPEG 2000 compression and transparency. For most archiving purposes, PDF/A-1b is sufficient and universally supported.
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