Compare PDF

Compare PDF finds what changed between two versions of a document — a contract before and after the other side's edits, or a report against last month's. It compares the text word for word and lists every place it differs, with the words around it and the page it is on in each file: struck-through words were removed, underlined words added. A one-word edit reads as that word, even when the line around it was reflowed, and a page added in the middle does not make everything after it look changed. It also compares the pages by look, side by side, and shows each page that looks different with the changes in red — so a new signature, a swapped logo or a scanned page shows up even where the text does not change.

1. Choose both PDFs, or drop them on the page. More than two is fine; you pick which two to compare.
2. Choose the Original and the Changed file.
3. Press Compare the files. Both are read and compared in your browser; a long document takes a few seconds.
4. Read the list: each change with its page, removed words struck through, added words underlined. Below it, the pages that look different, each with what changed in red.
5. Download the changed file with the changes marked — highlights and comments any PDF reader shows — or the report (.txt), with every change marked [-removed-] and {+added+}.

• Text is compared as the PDF stores it. Scanned pages are pictures with no text, so only the look compares them; run OCR PDF on both first to compare their words. Columns and tables come out in the order the file keeps them, which can make a moved block read as removed and added.
• Pages are compared by look side by side — page 1 with page 1 — up to 300 pages, at a low resolution that catches a changed word, picture or signature but not a hairline. After an added or removed page, every later page looks different; the text comparison is the one to trust then.
• Formatting alone — a word made bold, a different font or colour — changes no words, so it shows only if it changes the look enough.
• The two files are compared as they were added: changes made in the workspace since are not part of it.
• Files up to 300 MB each. A password-protected PDF asks for its password when added.
• Both PDFs are read and compared in this browser tab. Neither is uploaded to ToolsDev or anyone else, and nothing is saved: closing the tab ends the session. Contracts and drafts are exactly the documents that should not leave your device, and here they do not. The page downloads its own code, and pdf.js's fonts and decoders when a page needs them, from toolsdev.in; none of those requests carries your documents.

Yes — that is what this is for. Add the old and the new version, compare them, and every changed word is listed with its page in each, so you can check each edit instead of rereading the whole contract.

Something other than words changed: a picture, a stamp, a signature, a line in a table, or the page moved down because something was added above. The red marks show where.

Yes, for PDFs that store their text properly: the words are compared as text, in any language. Some older Indian-language PDFs use fonts that store the letters in a private order; their text compares as garbled, and only the look comparison is reliable for them.

Yes. Download the changed file with the changes marked: added words are highlighted in green, and a pink comment sits wherever words were removed or replaced, saying what was there. It is a copy, checked like every file made here; your files are not changed.