Compare PDF Files

Use the Compare tool to identify differences between two versions of a PDF. You can compare text, images, and annotations.

Before you begin

• Open both documents in Nitro PDF Pro
• Ensure both files are converted to PDF if needed

Compare documents (content comparison)

Use this option to compare text-based documents and view changes in context.

1. On the Review tab, in the Document group, click Compare
2. In the Compare Documents dialog box, select Compare text-based documents, then click Next
3. Select the Original Document and Changed Document
4. Click Preferences to adjust comparison settings (optional)
5. Select the pages to compare:
   1. All: Compare the entire document
   2. Current page: Compare the visible page
   3. Pages: Enter a page range (for example, 3–5)
6. Click OK to start the comparison

Compare scanned or image-based documents (visual comparison)

Use this option to compare documents at pixel level

1. On the Review tab, click Compare
2. In the Compare Documents dialog box, select Compare scanned and image-based documents, then click Next
3. Select the Original Document and Changed Document
4. Click Preferences (optional)
5. Select the pages to compare:
   1. All
   2. Current page
   3. Pages
6. Click OK to start the comparison.

View comparison results

After comparison, Nitro PDF Pro opens a new tab showing the results:

• Content comparison: Highlights differences in text, images, and annotations in context.
• Visual comparison: Shows only pixel-level differences between documents.

Color coding is based on settings in Preferences.

Comparison types

• Content comparison: Detects and highlights changes in document content
• Visual comparison: Detects pixel-level differences in images and scanned files