PDF vs PDF/A: what is the difference?

What PDF/A is

PDF/A is defined by the ISO 19005 standard family and is meant for archiving. It is not a different file type: a PDF/A file has the .pdf extension and opens in any PDF viewer. The difference is a set of rules the file must follow so that it is self-contained and its appearance does not depend on the software or system that opens it.

A regular PDF is free to rely on things outside the file, which is convenient today and risky in the long run. PDF/A removes those dependencies.

The main rules PDF/A adds

The exact requirements vary by part of the standard, but the core ideas are consistent.

• All fonts must be embedded in the file, so text looks the same on every computer.
• Encryption is not allowed. A password-protected file cannot be PDF/A, because a future reader may not be able to open it.
• JavaScript and other executable content are not allowed.
• The file must not depend on external content such as linked fonts or referenced files.
• Colours must be defined in a way that does not depend on the device. In practice that means an embedded colour profile or an output intent.
• Descriptive metadata in XMP format must be present, which helps archives identify the document.

The versions and conformance levels

PDF/A-1 (2005) is based on PDF 1.4, PDF/A-2 (2011) on PDF 1.7 and adds features such as transparency and JPEG 2000, and PDF/A-3 (2012) additionally allows embedding files of any format. PDF/A-4 (2020) is based on PDF 2.0. Later parts do not make earlier ones obsolete; institutions often name the version they accept.

Within a part there are conformance levels. Level B guarantees that the pages look the same over time. Level A adds a tagged structure for accessibility and reading order. Level U, in parts 2 and 3, guarantees that text maps to Unicode so it can be searched and copied reliably.

How it differs from an ordinary PDF

A typical PDF made from an office program may embed only part of its fonts, may be encrypted to prevent copying, may include form scripts and may use colours tied to a specific screen. Any of these makes a file fail PDF/A. Conversely, a PDF/A file is often slightly larger, because fonts and colour profiles are stored in it.

PDF/A also does not mean the content is true, signed or legally valid. It only says the file is built to stay readable the same way. Whether a document has legal weight depends on its content and on the rules of the country or institution.

When you actually need PDF/A

You need it when someone requires it. Libraries, courts, public administrations, records offices and some tenders and e-filing systems ask for PDF/A for documents that must be kept for years. Companies with retention obligations sometimes use it internally as well. If no one has asked, an ordinary PDF is usually fine.

Always read the requirement itself. It will state the part and level, such as PDF/A-1b or PDF/A-2b, and creating the wrong one can mean a rejected submission.

What this site does and does not do

We do not currently convert files to PDF/A, and we cannot certify that a file conforms to it. Producing a valid PDF/A needs a converter and a validator, and the office programs and archiving software that offer a Save as PDF/A option are the usual route.

What you can do here is inspect a file. PDF Information shows whether a PDF is encrypted, has JavaScript, uses forms, is tagged, and which fonts and images it contains, so you can see why a file would not meet the rules. Nothing is uploaded.

Helpful tools when preparing a file

Repair PDF rebuilds a damaged file structure with QPDF in your browser, which can make a file that opens with errors usable again before you send it to an archiving tool. It cannot recover data that is truly missing.

Flatten PDF turns interactive form fields into fixed page content, which is a common step when archiving a completed form, because the answers can no longer change. Neither tool makes a file PDF/A on its own, and to check a finished file against the standard, use a dedicated validator such as the open-source veraPDF.