PDF Comparison
Overlay two versions of a PDF page and see what was added, removed or moved. Words are compared too.
Free · runs in your browser · nothing is uploaded
This PDF comparison tool checks two PDF files against each other and shows what changed between them. Drop the older file in Original and the newer one in Revised, and it lists every added, removed or changed word across all pages, with page numbers. It also overlays the two versions, so you can spot changes that words alone do not show, such as shifted layout or altered images. The tool is free, runs in your browser tab, and needs no account or sign-up. Nothing you drop in is uploaded.
Export the result as a changes CSV or an HTML report. Everything runs in the tab.
How to use the PDF comparison tool
- Drop the older version of the document into the Original drop zone.
- Drop the newer version into the Revised drop zone. If you put them in the wrong boxes, click Swap the two files.
- If a box asks for a password, type it in. The password stays in the tab.
- Read the default Picture overlay view. Dark pixels found only in the original show red, dark pixels found only in the revised show green, and pixels in both show grey.
- Switch to Side by side to see both pages. Removed words are boxed red on the original, and added words are boxed green on the revised.
- Switch to Changes only to get a list of every change, with links to each page.
- Before you read the results, tick Ignore upper and lower case or Ignore punctuation if those differences do not matter for your check.
Once you have the results, export them as a changes CSV or as an HTML report. The CSV has one row per change, and the report gives you the same findings in a page you can keep.
Use the page arrows to move through the pairs: page 3 of one file sits next to page 3 of the other.
How does a PDF comparison tool find changes?
The tool compares the words in both files across all pages and reports each change as removed, added or changed, with its page number. It also compares the dark pixels on each page, which catches differences that the word check cannot see.
| View | What it shows |
|---|---|
| Side by side | Both pages together. Removed words are boxed red on the original, and added words are boxed green on the revised. |
| Picture overlay | Dark pixels found only in the original (red), only in the revised (green), or in both (grey). It also shows the share of dark pixels that differ. |
| Changes only | A list of every change, with links to the matching pages. |
The overlay has “Forgive shifts of one pixel” switched on by default, so tiny alignment differences do not flood the result. If the two files have different page counts, the tool reports that too.
Does it detect formatting changes?
Yes, but formatting changes show up in the picture overlay, not in the word list. Fonts, images and layout changes that leave the words unchanged appear only in the overlay. Look at the red and green areas on each page to find them.
Scanned PDFs without a text layer have no words to compare, so use the overlay for those files as well. The tool does not run OCR, so it cannot read the text in a scan.
How do I read the colours in the overlay?
Grey means a dark pixel is in both files. Red means it is only in the original, and green means it is only in the revised. A line of text that moved a few pixels would show as red next to green, which the one-pixel switch forgives. A whole paragraph that shifted down shows as red and green side by side, and the share of differing dark pixels rises accordingly.
Frequently asked questions
How can I compare PDF files for free?
Open this page and drop the two PDFs into the Original and Revised boxes. The comparison costs nothing and needs no account, sign-up, or cookies.
What happens to the documents I compare?
The files stay in your browser tab. Nothing is uploaded, and the page’s security policy only allows requests to scrubproof.com.
Can it open password-protected PDFs?
Yes. When a file needs a password, a box asks for it, and the password stays in the tab.
Can I compare scanned PDFs?
Only through the picture overlay. A scan without a text layer has no words for the word check to compare, and the tool has no OCR.
What if the two PDFs have different page counts?
The tool pairs pages by number and reports the difference in page counts. Check the extra pages yourself, since the overlay can only compare pages that exist in both files.
Does a PDF comparison work without an internet connection?
It does once the page has loaded. The tool keeps working with the network switched off after the first load. The PDF engine, about 2 MB, downloads the first time you open a file.
What does the exported file contain?
The changes CSV has five columns: change, page_a, text_a, page_b and text_b. The HTML report is the other export option.
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