Compare PDF Files
Compare the text of two PDF versions word by word; removed and added text is marked by page in a color report
Your files stay with you. Conversion happens inside the browser; no file is ever uploaded to a server.
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How it works
A typical case: your landlord or a client sends a "revised" lease or contract as a PDF, and you want to know what changed without rereading every page. Select the PDF you already had first, then the new one, and press Compare. The tool reads the text of both files page by page, compares it word by word and builds a report. The result line says, for example, "2 changes · 3 removed, 4 added words · pages: 2, 5". Open the downloaded .html report in your browser: each change gets a row with its page numbers and the surrounding sentence; removed text is red and struck through, added text is green and underlined. Below the table, the full text of the new version is shown with every change marked. If you selected the files in the wrong order, the colors come out reversed; choose "Swap" and compare again.
This tool is also known as compare pdf, compare two pdf files, pdf diff, find differences between two pdfs, compare pdf documents online, pdf compare tool.
What is PDF text layer?
PDFs saved from Word or another program store every character as real text, with its font and position; this is the text layer. The comparison runs on that layer. A PDF made by a scanner or a phone camera is just a picture of the page with no text layer, and for such a file the tool reports that no readable text was found instead of guessing.
What is Diff report?
A diff is the shortest list of deletions and insertions that turns one text into another; programmers use the same method to compare versions of code. Words present in the old file but missing in the new one count as removed, and the reverse as added, so a single replaced word shows up as one removal plus one insertion.
How is comparing PDFs different from comparing pasted text?
A text comparison tool needs you to copy and paste both texts, and text copied out of a PDF often arrives with broken lines and extra spaces, and without any page numbers. The PDF comparison reads the files directly, tells you on which page each change sits, and ignores spacing that comes from the PDF layout rather than from the words. With two PDFs, use this tool; with two pasted texts, use text compare.
Only the text is compared, not the look
The tool looks at the words in both files. A new font, color, logo, picture or layout does not appear as a change, and making a sentence bold is not a difference. A scanned page, such as a signed copy, has no text and cannot be compared.
Spacing differences are ignored on purpose: the gap between two words in a PDF usually comes from typesetting, and the same text saved by two programs can have different spacing. Counting it would flood the report with meaningless changes. The page column shows where the change starts in the old and the new file (3 → 4 means it moved from page 3 to page 4).
Word by word or line by line?
Word by word suits contracts, leases, letters and quotes: "one year" becoming "two years" appears as a single change.
Line by line suits price lists, inventories and numbered clauses: it tells you which line was changed, added or removed; even if only one number in a line changed, the whole line is marked.
Frequently asked questions
How do I find the differences between two PDF files?
Select the old PDF first and the new PDF second, then press Compare. The tool compares the text word by word, gives the number of changes and their pages in the result line, and puts the details into a color .html report.
Can I compare scanned PDFs?
No. A scanned PDF is a picture of the page with no readable text inside. Run it through OCR software first to get a PDF with text; if a file has no text, the tool names it in the error message.
The colors are the wrong way round. Why?
The files were selected in reverse order: the tool treats the first one as the old version. Choose "Swap" under "Which file is the old version?" and compare again. The top of the report names which file was treated as old and which as new.
Are my files uploaded?
No. Both PDFs are read and compared inside your browser, and the report is created on your device. No file leaves this page.