PDF/A: The Archiving Format Your Invoices Should Use

A normal PDF may not open correctly in ten years. PDF/A is a standard designed specifically for long-term archiving of documents like invoices.

What PDF/A is

PDF/A is a version of PDF that embeds everything needed to render the document — fonts, colours, images — so it looks the same on any system, now and in the future.

PDF/A is an ISO standard that removes the features that make ordinary PDFs fragile over time. It requires everything the document needs to be embedded within the file itself.

By embedding fonts and images and forbidding external dependencies, PDF/A guarantees the document renders identically regardless of the software used to open it.

There are several PDF/A versions, but for invoices the key point is the same: a self-contained file that remains readable for years without relying on outside resources.

• Embeds fonts and images.
• Self-contained and stable.
• Designed for long-term readability.

Why it matters for invoices

Invoices must be kept for 10 years. A PDF/A file will still be readable in a decade, while a normal PDF can break if fonts or dependencies change.

Swiss law obliges businesses to keep accounting records, including invoices, for 10 years. That decade-long horizon is exactly the period where ordinary PDFs start to fail.

A normal PDF can depend on fonts or features that no longer exist in future viewers, making text unreadable or misplaced. PDF/A removes that risk by construction.

Archiving in PDF/A is not just about readability. It is about producing a stable, verifiable record that still looks like the original invoice years later.

• Invoices must be kept for 10 years.
• Ordinary PDFs can break over time.
• PDF/A keeps the record stable.

Use it for archives

Separate the invoice you send from the invoice you keep. The client can receive any convenient PDF, while your archive copy is exported as PDF/A.

Most invoicing tools can export PDF/A or produce it by default for archive copies. Check the export settings and set PDF/A as your archiving default.

Make the choice a rule, not a preference. Every invoice that leaves your system for the archive should be in PDF/A, without exception.

• Send a normal PDF to clients.
• Archive the copy as PDF/A.
• Make PDF/A the archiving default.

Keep the archive sound

PDF/A only helps if the file is stored safely and found again later. Combine the format with a reliable storage and naming scheme.

Use a consistent file name that includes the invoice number and date, so an archived invoice can be located instantly years later. A random name defeats the purpose.

Store the archive in more than one place, following the usual backup discipline. A perfectly formatted PDF/A that is lost is still lost.

Check occasionally that a sample of archived files still opens correctly. A short verification now confirms the whole archive is still sound.