PDFs Screen reader compatibility

Accessibility
Nov 26, 2024

Screen reader compatibility for PDF accessibility features. Built-in browser PDF engines are used where possible. For IE11, the Acrobat Reader plugin is used.

The results include two types of test:

  • Expected to work - these tests show support when accessibility features are used correctly
  • Expected to fail - these tests show what happens when accessibility features are used incorrectly

Reliability by user agent

The solid area in the graph shows percentage of tests that pass in all tested interaction modes. The cross hatched area shows partial passes that only work in some interaction modes.

An example of a partial pass is when form labels are read when tabbing, but ignored in browse mode.

ComboVersionsReliabilityTest Changes
JAWS ChromeJAWS 2024.2409.2 with Chrome 131
JAWS EdgeJAWS 2024.2409.2 with Edge 131
JAWS FirefoxJAWS 2024.2409.2 with FF 128
5 better
JAWS IEJAWS 2019.1912.1 with IE11
2 better
NVDA ChromeNVDA 2024.4 with Chrome 131
NVDA EdgeNVDA 2024.4 with Edge 131
NVDA FirefoxNVDA 2024.4 with FF 128
5 better
NVDA IENVDA 2019.2 with IE11
VoiceOver MacVoiceOver macOS 14.6 with Safari 17.6
2 better
VoiceOver iOSVoiceOver iOS 17.7 with Safari iOS 17.7
WindowEyes IEWindowEyes 9.2 with IE11 
Dolphin IEDolphin SR 15.05 with IE11 
SaToGo IESaToGo 3.4.96.0 with IE11 
Average Including older versions

The average includes all versions, but some browser/AT combinations have tests for multiple versions (NVDA / JAWS / VoiceOver), while others only have tests for a single version (SaToGo and Dolphin).

Reliability trend

100%80%60%40%20%0%201520162017201838%201950%202034%202134%202239%202336%202448%

Expected to work

These tests use conformant HTML or WCAG sufficient techniques and might be expected to work in screen readers. This doesn't always happen.

Screen ReaderNVDAJAWSVoiceOver
BrowserEdgeFFCrEdgeFFCrMaciOS
52%PDF1 Image with alt text
20%PDF16 Document default language set to French
68%PDF18 Document with doc title
30%PDF19 Phrase language set to German
55%PDF4 Decorative image marked as artifact
34%PDF6 Table with header markup
34%PDF6 Table with header markup and alt text
46%PDF9 Document with headings

Expected to fail

These tests use non-conformant HTML or WCAG failures and are expected to fail in screen readers.

Screen ReaderNVDAJAWSVoiceOver
BrowserEdgeFFCrEdgeFFCrMaciOS
100%PDF image with blank (single space) alt text
100%PDF image without alt text
100%PDF no headings
100%PDF table without header markup
100%PDF untagged
55%PDF with doc security
100%PDF with no doc title

Key

  • Stable - works, or doesn't cause problems, in all versions of a specific combination of screen reader and browser
  • Better - works, or doesn't cause problems, in the most recent version of a specific combination of screen reader and browser (improvement)
  • Worse - causes problems in the most recent version of a specific combination of screen reader and browser, but used to work in older versions (regression)
  • Broken - causes problems in all versions of a specific combination of screen reader and browser

Test notes

All tests were carried out with screen reader factory settings. JAWS in particular has a wide variety of settings controlling exactly what gets spoken.

Screen readers allow users to interact in different modes, and can produce very different results in each mode. The modes used in these tests are:

  • Reading Content read using the “read next” command in a screen reader
  • Tabbing Content read using the “tab” key in a screen reader
  • Heading Content read using the “next heading” key in a screen reader
  • Touch Content read when touching an area of screen on a mobile device

In the “What the user hears” column:

  • Commas represent short pauses in screen reader voicing
  • Full Stops represent places where voicing stops, and the “read next” or “tab” or “next heading” command is pressed again
  • Ellipsis … represent a long pause in voicing
  • (Brackets) represent voicing that requires a keystroke to hear