Reading order is one of those PDF accessibility issues that can be easy to miss because the document may look completely fine on the page. Headings are in place, columns line up and charts sit where they should, but that visual layout doesn’t necessarily tell you how a screen reader will move through the content.
Screen readers rely on the PDF’s underlying tag structure to determine what gets read first, what comes next and how different elements relate to one another. If that order is incorrect, the content can become confusing even when the design itself looks perfectly organized.
In this guide, we’ll look at how PDF reading order works, how to check it and what you can do to fix common issues before publishing.
What is a reading order in a PDF?
PDF reading order, also called logical reading order, is the logical sequence in which assistive technologies access and present the content of a document. According to W3C, reading order is determined primarily by the order of elements in the PDF’s tag structure rather than simply by where they appear visually on the page.
A correct reading order allows someone using a screen reader to move through headings, paragraphs, images, tables and other content in a clear, logical sequence.
Reading order vs. tag order: What’s the difference?
Tag order is the sequence of elements in a PDF’s tag structure, while reading order is the sequence in which that content is presented to assistive technology. In a properly structured PDF, the tag order should create a logical reading order.
This is why a PDF can contain all the right tags and still have an accessibility problem if those tags appear in the wrong sequence.
Reading order vs. tag order vs. visual order
Reading order, tag order and visual order describe different parts of how someone moves through a PDF.
- Visual order is how the page appears to be organized.
- Tag order is how elements are sequenced in the PDF’s tag structure.
- Reading order is the sequence assistive technology presents to the user.
In a simple one-column PDF, the intended sequence may be straightforward: heading, paragraph, image, caption, then the next paragraph. With multiple columns, sidebars, charts, links or form fields, it becomes much easier for that sequence to go wrong.
That is why reading order needs to be checked separately from the visual layout.
Why reading order matters for PDF accessibility
Broken reading order makes a PDF inconvenient to navigate and can change what the content means.
Consider a chart showing how employees commute to work: 42% drive, 31% take public transit and 18% walk or cycle. But if a screen reader announces “42%, 31%, 18%” before reading the chart title and category labels, you hear a string of numbers (i.e., 42%, 31% and 18%) without any context.
The same problem can show up throughout a PDF:
- Paragraphs may be announced out of sequence
- Links can lose the text that gives them context
- Image captions can become separated from their images
- Charts can become difficult or impossible to interpret coherently
- Form instructions can be announced too early or too late to help someone complete the relevant field
This is why having tags alone does not make a PDF accessible. The tags also need to follow a logical sequence.
Here’s what broken reading order can look like in practice: the screen reader jumps across columns instead of following each section logically.
WCAG 2.2 Success Criterion 1.3.2, Meaningful Sequence, requires a correct reading sequence to be programmatically determinable when the order of content affects its meaning. It’s a Level A requirement.
W3C even uses a multi-column document as an example:
Example 1: In a multi-column document, the linear presentation of the content flows from the top of a column to the bottom of the column, then to the top of the next column.
So when you check PDF accessibility, reading order needs to be reviewed alongside the tags themselves.
Where does PDF reading order commonly break?
PDF reading order commonly breaks when content doesn’t follow a simple top-to-bottom sequence. This includes multi-column layouts, sidebars, callout boxes, image captions, headers and footers.
1. Multi-column layouts
Multi-column PDFs can be tricky because the order that feels obvious when you look at the page may not be reflected in the PDF’s tag structure. This is common in reports, brochures and newsletters and other content arranged across different sections of the page.
Take this newsletter, for instance:
Someone looking at the page will understand the intended path almost instantly:
- Read the heading
- Read the left column from top to bottom
- Move to the top of the right column and continue downward
A screen reader can’t work that out from the layout alone. It follows the order defined in the PDF’s tag structure.
If that sequence is wrong, it might move from one text block to another across the page, read a caption before the image it belongs to or jump to a separate section before finishing the current one.
The frustrating part is that nothing necessarily looks broken. You can proofread the PDF on screen, send it through stakeholder review and publish it without ever noticing the problem.
That’s why a visual review alone can’t confirm an accessible PDF’s reading order. You need to inspect the sequence that assistive technology will actually encounter.
A pull quote, note or sidebar often sits neatly beside the main text without disrupting someone looking at the page.
But if its position in the tag order follows where it sits on the page rather than where it makes sense in the content, a screen reader can encounter it at the wrong moment.
That could mean hearing half a sentence, an unrelated three-line callout and then the rest of the sentence. The callout itself isn’t inaccessible. Its placement in the reading sequence is the problem.
3. Image captions
Images, their alt text and their captions need to make sense as a unit.
If a caption is announced long before or after its related image, the reader has to work out what it refers to. That becomes especially confusing when several images appear close together.
Some elements that help visually can become pure noise when they enter the reading order.
Imagine hearing the company name, document title, page number and a decorative graphic announced every time you move to another page of a 30-page report. Repeated headers, footers, page numbers and decorative elements generally shouldn’t interrupt the main content when they don’t add meaningful information.
This is where good PDF tagging involves more than putting everything into a sequence. Some elements need to be excluded from the meaningful reading flow altogether.
How to check the reading order of a PDF?
To check PDF reading order, follow the sequence in which assistive technology will encounter each element rather than relying on how the page looks.
You can do this after export with a PDF accessibility checker such as PAC or Adobe Acrobat. Another option is to review and adjust the tag order while creating the document with accessible PDF makers like Venngage.
Check reading order with PAC or Adobe Acrobat
If you’ve already exported your PDF, use PAC or Adobe Acrobat to check the order in which assistive technology will present its content.
In PAC, open the PDF and use the Screen Reader Preview (eyeball icon at the bottom) to see the document as a linear sequence. Read through it from the beginning and check whether headings, paragraphs, images, captions and other elements appear where you expect them.
For example, make sure:
- Headings appear before the sections they introduce
- Paragraphs aren’t interrupted by unrelated content
- Columns are read in the intended order
- Captions stay with the relevant images or tables
- No important content is missing from the sequence
PAC also shows the structure of individual elements. Headings, for example, display their heading level, while alternative text appears alongside figures. This can help you spot cases where the reading order is correct but the underlying structure still needs attention.
Source: axes4
For a deeper walkthrough of this method, see our guide on how to check PDF accessibility with PAC.
You can perform a similar check in Adobe Acrobat by opening the Tags panel and following the tag tree from top to bottom. Compare that sequence with the way the content is meant to be read on the page.
Source: Adobe Acrobat
Check and adjust reading order in Venngage before export
Venngage’s Accessible PDF Maker lets you build accessibility into the document while you’re still designing it. You can add alt text, set headings and document language, check color contrast and manage the reading order before exporting the file as an accessible PDF.
Go to File > Accessibility > Edit tag order. The Tag Order panel shows the sequence of elements in your document. Go through the list from top to bottom and drag any elements that are out of place into the correct position.
Here’s a quick guide to setting the reading order:
Once the sequence looks right, go to File > Accessibility > Check Accessibility and expand Logical Tag Order. After reviewing the document, check the box confirming that “The document has a logical reading order.”
You can then export the document as an accessible PDF with the reading order you’ve set.
The reading order you set in Venngage stays intact in the accessible PDF, so you don’t have to re-tag the sequence after export.
Venngage helps export the accessible PDF without adding a separate reading-order remediation step after export.
How do you fix reading order in a PDF?
To fix reading order, you need to change the order in which the PDF content is tagged. Simply moving things around on the page may not change what a screen reader reads first.
A practical fix looks like this:
- Identify the first element that appears out of order: Open the Tags panel, Order panel or screen reader preview and follow the page from the beginning. Stop at the first point where the content no longer follows the intended sequence.
- Move that element to the correct position in the tag order: For example, if the first paragraph in the right column appears before the final paragraph in the left column, move its tag so the entire left column is completed first.
- Check nearby supporting elements: Make sure captions follow the correct image or chart, callout boxes do not interrupt paragraphs and sidebars appear at a point where their content makes sense.
- Review complex elements separately: For charts, check that the title and context come before the data. For tables, make sure the table structure and header relationships are preserved rather than treating the cells as unrelated text.
- Run through the sequence again: After making changes, start from the beginning of the page and check the reading order again. Then test the final exported PDF to make sure the corrected sequence has been preserved.
The key is to fix the first point where the sequence breaks, rather than trying to rearrange the whole page at once.
How to set reading order for charts, infographics and tables?
For charts, infographics and tables, you need to make sure that titles, labels, data, descriptions and other supporting information appear in an order that makes the content understandable without relying on the visual layout.
1. Charts and infographics
Charts and infographics make reading order more complicated because you need several elements together to understand them, such as the title, labels, data, legend and supporting text. A screen reader encounters each of these elements one at a time, so their order matters.
A visual reader sees all its elements together, while a screen reader encounters them one at a time. That sequence needs to be deliberate.
For a chart, the order might be:
- Chart title
- Short explanation or key takeaway
- Data labels and values
- Legend, if needed
- Source or supporting note
Then check how the chart itself is tagged. If it is included as a single image, give it alt text that communicates the important information. If the title, labels, values and other parts are separate tagged elements, make sure they follow a logical sequence rather than being read according to where they happen to sit on the page.
For infographics, follow the same principle but work through the content section by section. Take this employee onboarding infographic, for example:
Visually, the numbered sections and positioning make the intended sequence obvious. But if the underlying tag order jumps from Step 1 to Step 4, reads an icon description, moves back to Step 2 and announces the title last, the visual story disappears.
This is why alt text alone doesn’t solve accessibility for data visualizations. Alt text can explain what a chart or graphic communicates, but the surrounding content still needs a logical structure when individual elements are available to assistive technology.
This is also where controlling reading order during design becomes useful.
In Venngage, open File > Accessibility > Edit tag order and review the sequence of elements in the Reading Order panel:
You can then drag elements into the intended order while their relationships are still obvious in the design, rather than discovering a scrambled sequence after exporting the PDF:
For charts and infographics in particular, that means accessibility becomes part of how you structure the visualization, rather than a repair job at the end.
Related: Accessible Document Flywheel: Solve the PDF Accessibility Problem
2. Tables
For people who depend on screen readers, a table needs more than rows and columns that look like a table.
In a properly tagged PDF table, screen readers can identify the table structure, recognize headers and associate those headers with the relevant data cells. That context helps a reader understand what each value represents.
Without that structure, the content may be announced in an order that doesn’t match the rows and columns you see.
Watch this video to understand how a screen reader navigates an accessible table.
As you can see, the relationships between headers and data are what make the table understandable. Design-wise, a table can look perfectly organized on the page but lack the underlying table structure that tells a screen reader which values belong to which headers.
Why fixing PDF reading order after export takes longer
Sure, you can fix the reading order after exporting a PDF. But by then, you’re fixing the PDF’s structure separately from the document you originally designed.
That often means opening the file in Acrobat or other PDF accessibility checker tools, locating the relevant tags and manually moving them into the correct sequence. In a complex report with dozens or hundreds of tagged elements, even finding the source of a reading-order problem can take time.
There’s also a practical workflow problem. At the design stage, it’s obvious that a caption belongs to a particular chart or that a callout should follow a certain paragraph. After export, you’re working through the PDF’s underlying structure and reconstructing those relationships.
Venngage takes the upstream approach. You can review and adjust reading order while you’re still designing, when the intended relationship between elements is clear. Its accessible templates also start with a logical reading sequence already in place.
For teams producing PDFs regularly, and at scale, avoiding the common pitfalls during design is usually a cleaner workflow than repeatedly remediating it afterward.
Reading order in right-to-left and multilingual PDFs
There isn’t one universal “correct” reading direction. Logical reading order depends on the document’s language and how its content is intended to be read.
Arabic and Hebrew documents, for example, may follow a right-to-left (RTL) sequence rather than the left-to-right order you’d expect in English. Mixed-language PDFs can be more complicated when both directions appear in the same document.
Set the PDF’s document language correctly, then test the actual screen-reader output. For multilingual documents especially, don’t assume that a sequence that looks logical on the page will be interpreted the same way by assistive technology.
Make reading order part of your design process
Reading order is easy to miss precisely because you can’t see it in a visual review. A PDF can survive rounds of proofreading and design approval while remaining confusing for someone navigating it with a screen reader.
That’s a strong argument for dealing with reading order before remediation becomes necessary. Venngage’s accessible templates give you a logical starting structure, while the drag-and-drop Reading Order panel lets you review and adjust that structure before accessible PDF export.
Because a polished PDF isn’t finished when everything is in the right place. It’s finished when everyone can encounter it in the right order.
FAQs
Still have questions about PDF reading order? Let’s clear up a few of the common ones.
What is a reading order in a PDF?
PDF reading order is the logical order in which a screen reader announces document content. It’s controlled by the PDF’s underlying tags and structure, rather than the visual position of text, images and other elements on the page.
Why does reading order matter for accessibility?
Reading order helps screen reader users understand PDF content in the intended sequence. Incorrect order can separate headings from paragraphs, captions from images, chart labels from data or form instructions from the fields they explain.
How do I check the reading order of a PDF?
Check PDF reading order using a tag tree, Order panel or screen reader preview in a tool such as PAC or Adobe Acrobat. Follow the sequence from beginning to end rather than relying on the PDF’s visual layout.
How do I fix the reading order in a PDF?
Fix PDF reading order by rearranging the document’s tags into a logical sequence. For example, read a complete left column before the right and place captions, callouts and sidebars near the content they support.
Why does my two-column PDF read out of order?
A two-column PDF may read incorrectly when its tag order follows the position of elements rather than the intended column sequence. The screen reader may then jump between columns instead of finishing one before starting the next.
Does reading order affect charts and tables in PDFs?
Yes. Charts need their title, context, data and legend in a logical sequence. Tables need proper table tags and header relationships so screen readers can identify how each data cell relates to its row or column.
