PDF accessibility
Tag Your Untagged PDF
"Document is not tagged" is the #1 accessibility failure. This adds the full tag layer to the PDF you already have.
Tags are the hidden skeleton of an accessible PDF — the machine-readable outline (headings, paragraphs, lists, figures, tables) that screen readers walk instead of the raw ink. Most PDFs ship without any: the export setting was off, or the generating tool never wrote them. Adding tags afterward by hand in Acrobat is slow, fiddly expert work — which is what per-page remediation services actually bill you for. Ceereo automates it for born-digital documents: content analyzed, roles assigned, reading order sequenced, furniture marked as artifacts, and the whole tag tree threaded into your original file with a pixel-diff proving nothing visible moved.
Pixel-identical output Minutes per document Try without signing up
Last updated: August 6, 2026 · Reviewed by the Ceereo team
Free audit, no signup — your full report opens on the next page.
How it works
From upload to accessible PDF in four steps
The fastest way from an inaccessible PDF to a tagged, verified one — no tag panel, no service queue, no visual changes.
- Step 1
Upload your PDF
Drop in the PDF you need to make accessible. Your file is processed only to audit and remediate it, and is never used to train models.
- Step 2
The document is audited
Every PDF/UA and WCAG machine check runs: tags, reading order, language, title, alt text, font embedding and text integrity.
- Step 3
The structure is written in
Headings, paragraphs, lists, tables and figures are tagged in reading order, with headers and footers marked as artifacts to be skipped.
- Step 4
Download the accessible PDF
Get your own file back with a full tag structure, re-audited and pixel-compared so you can prove nothing visible changed.
In short
An untagged PDF has no machine-readable structure, so screen readers get raw ink order — the single most common accessibility failure. Tagging adds the hidden outline (headings, paragraphs, figures, reading order). Ceereo writes that tag layer into your existing born-digital PDF automatically, visually unchanged and machine-verified.
What are PDF tags and why do they matter?
Tags are invisible structural labels — Heading 1, Paragraph, Figure, Table — arranged in reading order inside the PDF. Assistive technology navigates by them: jump between headings, read cells by column, skip decorations. Without tags a screen reader can only guess from raw drawing order. Tagging is therefore the foundational fix; nearly every other accessibility repair builds on it.
The foundational fix
Everything else stands on the tags
Alt text needs a Figure tag to live on; reading order is the sequence OF tags; heading navigation is the tag tree. That's why 'document is not tagged' outranks every other finding — and why fixing it first collapses most of the rest of your audit.
Features
Why teams choose Ceereo
Full role assignment
Headings by level, paragraphs, figures — assigned from real layout analysis.
Artifacts handled
Repeating headers/footers marked so readers skip them — a detail hand-taggers often miss.
Original file preserved
Tags are inserted into your PDF's existing content — pixel-diff verified.
Use cases
Where Ceereo works best
The classic failure
Checker said 'not tagged' — this is the direct fix.
Legacy libraries
Years of published untagged PDFs, fixed per document instead of per page.
Toolchain gaps
Your generator (or print-to-PDF) never writes tags; repair after the fact.
Why not do it by hand?
Ceereo vs. doing it manually
Remediating a PDF by hand in Acrobat's tag panel takes days and rarely verifies clean the first time. Here's the difference.
Output quality
What the remediated PDF looks like
Every run produces a tagged, machine-verified PDF that is pixel-identical to your original. Here's what you get.
- Complete tag tree: structure elements + reading order + artifacts
- Metadata repaired: language, title, viewer preferences
- Machine re-verification included
- Visually identical output, proven per page
Topic cluster
Related PDF accessibility tools
Other ways to audit and fix your PDFs for ADA, 508, and EAA compliance.
Fix Your PDF's Reading Order
When a screen reader jumps from headline to footer to column three, the file's structure is wrong — not the reader. This rebuilds it.
fixstructurePDF Remediation, Without the Per-Page Invoice
Human remediation services charge $3–10 per page and take days. The machine-checkable layer — most files' actual problem — takes minutes here.
fixGenerate Alt Text for Your PDF's Images
Every meaningful image needs a description a screen reader can speak — written into the PDF's structure, not pasted in a document nobody ships.
structureConvert Your PDF to Section 508 Compliance
Section 508 reviews start with the same automated checks every time. Pass them with a tagged, verified PDF — produced from your original in minutes.
fix
Frequently asked questions
How is this different from Acrobat's Autotag?+
Same category of operation — automated tagging — but self-serve, verified (machine re-check + pixel-diff shown to you), priced per document, and honest about inputs it declines (scans, forms) instead of tagging them badly.
Do tags change file size or compatibility?+
File size grows slightly (the structure data); compatibility is unaffected — tags are part of the PDF standard and invisible to normal viewers.
My PDF is a scan — can you tag it?+
No — a scan has no text to tag; it needs OCR reconstruction first. The tool detects this and says so rather than producing junk tags.
Add the missing tags
Upload your untagged PDF; download the structured, verified version.