Comparing PDF Documents

You can compare two similar PDF documents (e.g., two versions or revisions of a document) to determine differences between them or to verify if approved changes have actually been made. The comparison result is displayed in a temporary file that you can save if required.

To compare documents

  1. Select Document > Compare Documents…. The Compare Documents dialog box appears.

  2. Accept the currently active open document offered as the older one, or click Browse… to select another. The Open dialog box appears. Under Revision, select from any available revisions of the document.

  3. Accept an open document offered as the newer one, or click Browse… to select another. The Open dialog box appears. Under Revision, select from any available revisions of the document.

  4. Choose a comparison type: View visual and text differences (Visual) or View text differences (Text).

  5. For visual type select a markup color and analysis type: Thorough (slower comparison with a higher number of smaller areas), Balanced, or Overview (faster comparison with a lower number of bigger areas). For text type you can include formatting differences (font name, size, attributes, etc.).

  6. Select a report type for the comparison result: Side by Side or Combined.

Side by Side report: First, a summary page is displayed that contains the type of comparison (Visual or Text), the names of the older and newer documents, and either a message saying that both documents are identical, or the summarized comparison results as follows:

For textual comparison, the number of words:

  • added in the newer document

  • deleted from the older document

  • found in both documents (match)

  • differing in formatting only (if specified)

For visual comparison:

  • number of identical pages

  • number of differing pages

  • number of pages added or deleted (for documents with different numbers of pages)

For documents that were not found identical, the summary page is followed by pages of both documents next to each other with markups showing differences (e.g., strikethrough for deleted words, underline for added words, boxes for matching words, clouds for differing graphics, etc.). For comparison purposes, blank pages are added to the shorter document to equalize the numbers of pages.

Combined report: A consolidated document is created that displays the newer version of the document. A sticky note comment on the first page contains basically the same information as described for the summary page of a Side by Side report. Areas where differences were found are marked up. Hover with the Hand tool within a markup area to view the older content.  


To compare parts of documents

You may want to compare specific parts of documents only. First, perform Split Document for both of them, and then compare the resulting segments.


To compare special attributes

For a visual comparison, specific attributes such as notes, highlights, markups, watermarks, signatures, etc. are considered as “normal” graphical objects and are included in the comparison.

For textual comparison, texts within text boxes, header/footer texts or stamped texts are considered as “normal” texts, but annotation texts are excluded from the comparison.


Text differences are usually best displayed in Side by Side format, while for visually-based documents a Combined format may be preferred.

You can also compare a PDF document with a Word document.

Comparing PDF Documents