Compare PDF

How to compare two PDF files

1. 1

   Load the original Drop the older version on First PDF (original), or click that area to choose it. Its name and page count appear above the left pane.

2. 2

   Load the new version Do the same with Second PDF (to compare) on the right. The first page of each file then shows side by side.

3. 3

   Analyze the differences Press Analyze differences. When it ends, the view switches to Text mode and the toolbar counts the words removed, added and changed.

4. 4

   Go through the changes Click a number after Pages with differences to open that page, or move with the arrows. The panel under the text lists the differences found on the current page.

5. 5

   Check another pair Press Change file to clear both files and start again.

How pages and words are matched

Page 1 of the original is compared with page 1 of the new version, page 2 with page 2, and so on. When one file is longer, its extra pages are compared with an empty page.

Because pages are paired by number, a page inserted or removed in the middle shifts every page after it, and those pages then usually show differences. Align the files first: take the extra page out of a copy with Delete Pages, or keep only the matching range with Extract Pages, then run the comparison again.

On a given page, the tool checks which words are present, not where they sit. A word counts as removed when it is on the original page but nowhere on the same page of the new version, and as added in the other direction. When a removed word and an added word are more than 60% alike, the pair is shown as a change, like a year going from 2025 to 2026. Such a pair still counts as removed and as added too, and repeated words are paired with each other, so three copies of 2025 turned into 2026 give nine changes: the totals count words, not separate edits.

Matching is exact. A capital letter or a punctuation mark attached to a word makes it a different word, so "Total" and "total", or "total" and "total:", show up as a change.

Visual mode and text mode

Visual mode shows both pages as they look, side by side, so you can compare them by eye. It computes no differences: a moved picture, a new logo, another font or a changed color is noticed only if you see it yourself. Under the pages, a button for each of the first 20 pages takes you straight to it, and after an analysis a red dot marks the pages with differences.

Text mode shows the text read from each page as one continuous block, without its line breaks or layout. A page with fewer than five characters of text shows "No text on this page" instead, even when the list under it reports a change there, such as a year. Removed words are highlighted in red in the original, added words in green in the new version, and changed words in yellow on both sides. The panel under the text lists up to 20 differences for the page, then how many more there are. Whenever the page text is shown, every word in that list is highlighted in it, whatever the alphabet. Words are compared exactly as written, with their punctuation and capital letters, so "2026." and "2026", or "Contract" and "contract", count as different words.

Before you rely on the result

• • The banner "Documents are identical ✓" means that no word was found missing or new on any page. It does not cover pictures, formatting, word order or file properties.
• • If neither file has a page with more than 10 characters of text, the analysis stops with the message "No extractable text found. PDFs may be scanned (images)." If only one of them is a scan, every word of the other one shows as a difference, so compare scans by eye in Visual mode.
• • The results disappear when you press Change file or leave the page. Note the page numbers listed after Pages with differences if you need them later.