What is PDF/A? The archive format explained, and how to convert to it
Updated · PDF Converter
You have been asked to submit a document “in PDF/A format”, and your file is already a PDF. Is that not enough? Usually not. PDF/A is a stricter version of PDF designed for one job: making sure a document will still open and look exactly the same many years from now. This guide explains what PDF/A is, when it is required, and how to convert a normal PDF.
PDF/A in one sentence
PDF/A is an ISO standard (ISO 19005) for long-term archiving: a PDF/A file must contain everything it needs to be displayed, and must not depend on anything that might disappear or change over time.
A normal PDF can rely on fonts installed on the reader’s computer, link to external content, run scripts or be encrypted. Any of these can make a document unreadable or look different in the future. PDF/A forbids them.
What makes a PDF a PDF/A?
- Fonts are embedded. Every font used in the document is stored inside the file, so text never depends on what is installed on the viewer’s device.
- Colours are defined. The file includes a colour profile (an “output intent”), so colours are reproduced consistently.
- Metadata is standardised. Title, author and the PDF/A identification are stored as XMP metadata.
- No encryption. Password protection is not allowed, because a lost password would make the archive unreadable.
- No active content. JavaScript, auto-run actions and similar features are forbidden.
Versions and conformance levels
You will often see a version number and a letter, such as PDF/A-2b. The number is the version of the standard; the letter is the conformance level.
| Version | Main difference |
|---|---|
| PDF/A-1 | The original version, based on PDF 1.4 and the most restrictive |
| PDF/A-2 | Based on PDF 1.7; allows features such as transparency, layers and JPEG 2000 images |
| PDF/A-3 | Like PDF/A-2, but allows files of any type to be embedded as attachments |
The level “b” (basic) guarantees reliable visual reproduction – the document will look the same. Level “a” (accessible) additionally requires a tagged structure for accessibility, and level “u” requires that all text can be mapped to Unicode.
When do you need PDF/A?
PDF/A is typically requested where documents must be kept for a long time or submitted to an official body: courts and electronic filing systems, national and corporate archives, public agencies, and organisations with records-retention rules. If a portal or authority asks for PDF/A, check which version and level it requires. If it only says “PDF/A”, PDF/A-2b is the level most widely accepted.
For everyday sharing – email, printing, reading on screen – a normal PDF is fine.
How to convert a PDF to PDF/A
- Open PDF to PDF/A and choose the PDF to archive.
- Press PDF to PDF/A. There are no settings – checks and fixes run automatically.
- Download your PDF/A-2b file and read the conversion report.
During conversion, the tool embeds missing standard fonts, attaches an sRGB colour profile, writes matching XMP identification and document information, and removes content PDF/A forbids – JavaScript, embedded attachments, auto-run actions and annotations without a visible appearance.
Unembedded Helvetica, Arial, Times and Courier fonts are replaced with the Liberation font family, which has identical character widths. Line breaks and layout therefore stay the same.
Tip: read the report. If something cannot be fixed automatically – for example an unembedded symbol or CJK font, or CMYK images – the report says so instead of claiming success. For compliance-critical submissions, confirm the result with a validator such as veraPDF.
Before you convert
- Encrypted PDFs cannot become PDF/A directly, because the standard forbids encryption. Remove the password first with Unlock PDF (you need to know it).
- Damaged files that show errors when opened can be fixed with Repair PDF first.
- Title and author end up in the archive’s metadata. If they are wrong or empty, correct them with Edit Metadata before converting.
The conversion runs in your browser, so the document is not uploaded.
Frequently asked questions
What is the difference between PDF and PDF/A?
PDF/A is a restricted form of PDF. It must embed all fonts, define its colours and carry standard metadata, and it may not use encryption, scripts or other content that could stop it from displaying correctly in the future.
Which PDF/A version should I use?
Use whatever the recipient specifies. When no version is given, PDF/A-2b is the level most courts, archives and agencies accept.
Will converting to PDF/A change how my document looks?
Normally not. Fonts that need substituting are replaced with metric-compatible equivalents, so text keeps the same positions.