Convert & archive
PDF/A Explained: What It Is and When You Need It
7 min readUpdated October 7, 2026By the PDF Studio team
If a court, university, tax office, or archive has asked you for a “PDF/A” and you are not sure what that means, you are not alone. It looks like an ordinary PDF — but it follows a stricter standard designed so that a document can still be opened and displayed identically decades from now.
What PDF/A is
An ordinary PDF can depend on things outside the file: fonts installed on your computer, links to external content, or features a future reader may not support. PDF/A (the “A” stands for archival) is a restricted version of PDF defined by ISO standards. It requires fonts to be embedded, colors to be defined, and forbids features that could break over time, such as encryption and external dependencies.
The practical result is a self-contained file that should look the same on any compliant reader in the future. That is why archives, courts, government agencies, and companies with record-retention rules require it for contracts, invoices, medical and legal files, and scanned archives.
The conformance levels
PDF/A comes in parts and levels. PDF to PDF/A offers five:
- PDF/A-1b — the original and most restrictive standard. It aims to preserve visual appearance.
- PDF/A-2b — built on a newer PDF version, allowing more modern compression and transparency. It is the usual default and widely accepted.
- PDF/A-2u — like 2b, and additionally guarantees that text can be searched and copied reliably (Unicode mapping).
- PDF/A-3b and 3u — like level 2, but they also allow other files, such as the source spreadsheet, to be embedded inside the PDF.
The letter at the end matters: “b” means basic conformance (appearance is preserved), “u” adds reliable text extraction. If the organization asking for the file has not said which level it needs, choose 2b. If it names a level, choose exactly that one.
How to convert a document
- 1Make sure the PDF is not password-protected. PDF/A forbids encryption, so remove any password with Unlock PDF first.
- 2If the document is a scan, run OCR PDF first so the text is searchable, then convert the result.
- 3Open PDF to PDF/A, add the file, choose the level, and convert.
- 4Download the new file. It is named after your original with the level added, for example report_PDF-A-2b.pdf.
Check the result
Open the converted file and look through it: fonts, images, and layout should match the original. Conversion is done on a best-effort basis, and unusual fonts, transparency, or content that depended on JavaScript or external links may be altered.
If you must prove compliance — for a court filing or a regulated archive — run the output through a validator. The free, open-source tool veraPDF is the usual choice and reports exactly which rules, if any, a file breaks.
What PDF/A is not
- It is not a guarantee of accessibility for screen readers; that is a separate property (tagged PDF).
- It does not make a scan searchable by itself — run OCR first.
- It does not compress the file. PDF/A files are often a little larger because fonts are embedded. If size matters, run Compress PDF first, then convert.