What Is PDF/A, and How Do You Convert a PDF to PDF/A?
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Sooner or later, an upload portal, a court registry, a tax office or a university library tells you that your file must be PDF/A. The document looks fine to you, it opens everywhere, and yet it is rejected. The reason is that PDF/A is not about how a file looks today; it is about whether it will look exactly the same in twenty years, on software that does not exist yet.
In this guide we explain what PDF/A actually requires, which version to choose, how we convert files with our tool, and how to check the result before you submit it, because a validator will usually be the first thing on the other side to look at your file.
What PDF/A is
PDF/A is an ISO standard, a restricted subset of normal PDF designed for long-term archiving. The core idea is that the file must be self-contained. Everything needed to display it correctly has to be inside the file, and anything that could change its appearance later is forbidden.
In practice that means a few concrete rules:
None of this changes the visible content of a typical document. It changes how that content is stored, so that a future viewer does not have to guess.
- Fonts must be embedded, not borrowed from the computer that opens the file.
- Colors must be defined in a device-independent way, so they look the same on any screen or printer.
- Encryption and password protection are not allowed.
- References to external content, such as linked files, and executable content such as JavaScript are not allowed.
- The file must carry standard metadata that identifies it as PDF/A.
Who asks for PDF/A, and which version
Courts and e-filing systems in several countries require or strongly prefer PDF/A for submitted documents. Public tenders often require it for bid documents. Universities ask for it when you submit a thesis to the library. Companies use it for invoices and contracts that must be kept for years under tax and commercial rules, and many national archives accept nothing else.
There are several parts and conformance levels, such as PDF/A-1, PDF/A-2 and PDF/A-3, each with levels like b (basic, visual appearance preserved) and a or u (with extra requirements for structure or text). Our tool produces PDF/A-2b, the most widely accepted level for everyday archiving. If a portal explicitly demands a different part or level, such as PDF/A-1a, follow its instructions and use software that targets that exact level.
How to convert a PDF to PDF/A with pdfdots, step by step
Unlike most of our tools, this one does not run in your browser. Conversion to PDF/A needs Ghostscript, so your file is uploaded over HTTPS to our server in Germany, converted and deleted immediately afterwards. We mark this on the tool page because we think you should know where your documents go. You need a free account; the free plan includes 3 tasks a day, and the paid Bronze, Silver and Gold plans raise the daily and size limits.
- 1. If the PDF is password-protected, remove the password first with Unlock PDF, because encrypted files cannot be valid PDF/A.
- 2. If it is a filled form, flatten it with Flatten PDF so the answers become part of the page.
- 3. Open PDF to PDF/A and drop the file into the box.
- 4. Click Convert to PDF/A and download the PDF/A-2b file.
- 5. For anything that will be checked by an authority, run the result through a validator such as veraPDF before submitting.
Why validation matters, and what can go wrong
We want to be straightforward about compliance: whether the converted file fully passes depends on the source. Most invoices, contracts, letters and reports exported from office software convert cleanly. Problems come from files with complex transparency, damaged or unusual fonts, or leftovers from heavy editing in several programs.
That is why we validate important files. veraPDF is free and open source; it reads the file and tells you which rules, if any, are broken. If it reports errors, the usual fixes are to re-export the source from the original program, run Repair PDF on a damaged file, or simplify the document before converting again. Submitting a file that merely claims to be PDF/A but fails validation can be worse than submitting an ordinary PDF, because some portals reject it automatically.
Practical tips for archiving and e-filing
Convert the final version only. PDF/A is an end state, and editing a PDF/A file afterwards in ordinary software can quietly break compliance. We keep the editable original next to the archived copy, named clearly, so we never wonder which one to send.
Watch the file size. Embedding fonts can make a file slightly larger, and many e-filing systems have strict upload limits. If size is a problem, address it before conversion by removing unnecessary pages or by compressing the source, then convert and validate. Compressing a PDF/A file afterwards with general tools may remove the PDF/A identification, so validate again if you do.
PDF/A is not the same as security or a signature
People sometimes assume PDF/A makes a document tamper-proof. It does not. It guarantees that the file can be displayed reliably in the future, not that nobody has changed it. Because encryption is forbidden in PDF/A, a PDF/A file cannot even carry a password. If you need proof of integrity, that comes from a qualified digital signature applied by suitable software, or from how and where the archive stores the file.
This is why we see PDF/A as one link in a chain: fill and flatten the document, sign it if needed, convert to PDF/A, validate, and store it somewhere with proper backups.
Frequently asked questions
Is my file uploaded for PDF/A conversion?
Yes. This tool runs on our server in Germany; the file travels over HTTPS, is converted with Ghostscript and is deleted immediately.
Which PDF/A version does the tool produce?
PDF/A-2b, the widely accepted level for long-term archiving of everyday documents.
Is the result guaranteed to be compliant?
No tool can guarantee that for every source. Check important files with a validator such as veraPDF.
Can I convert a password-protected PDF?
Remove the password first with Unlock PDF, because PDF/A does not allow encryption.
Will my document look different?
Normally not. PDF/A changes how fonts and colors are stored, not the visible layout.