Compare PDF files by their text
A new version of a contract, policy or specification rarely comes with an honest list of changes. To compare PDF versions here, drop both files: the text of every page is extracted and compared, and each difference is highlighted. Inside a changed sentence, the exact words that were added or removed are marked, so a changed number or a quietly inserted "not" stands out.
Sentences or lines
A PDF stores lines exactly as they were laid out. If the new version has a different font size, column width or margin, almost every line breaks in a different place, and a line-by-line comparison flags the whole document. Compare by: Sentences first joins the lines back together, including words hyphenated across a line break. It then puts one sentence per line, so only real edits show. Use Lines for content where line breaks matter, such as code listings, poems or addresses.
Example: these two layouts are treated as identical when comparing by sentences.
The supplier shall deliver the goods within
30 days of the order date.The supplier shall deliver the goods within 30 days
of the order date.Reading the result
- Side by side shows the original on the left and the new version on the right, with removed text in red and added text in green.
- Unified shows one column with removed lines (−) above their replacements (+).
- Changes with context hides long unchanged stretches, showing three lines around each change.
- Page markers add a line such as
--- Page 4 ---so you can find each change in the PDF.
Typical uses
Lawyers and procurement teams check a returned contract against the version they sent. Students see what a supervisor changed in a thesis. Product teams find what moved between two releases of a specification. In each case the .diff download keeps a record of the changes.
What is compared
Only the text is compared. Changes to images, colours, fonts or layout that do not change the words are not reported. Scanned PDFs have no text layer, so they cannot be compared this way without OCR. Password-protected files open once you enter the password.
To compare text you can paste instead, use the diff checker. To read a PDF's text on its own, use PDF to text.