Compare two PDF files

Put two versions side by side and see every word added, removed or moved, or overlay the pages and watch the differences light up.

How to Compare the PDFs

1
Drop both PDFs in
Add the older version to the first slot and the newer one to the second. The order matters: it decides which side counts as added and which as removed.
2
Pick text or visual comparison
Text mode reads the words on every page. Visual mode renders both pages and lays one over the other, so a moved logo or a changed font shows up too.
3
Read the changes and download the report
Step through the differences, then save a self-contained HTML report or a PDF one to send to whoever asked what changed.

Two ways to ask the same question

Text mode extracts the words from each page and runs a real diff over them, word by word, line by line or character by character. It tells you that a price went from 100 to 200: precise, quotable and easy to paste into an email. Visual mode never looks at the words: it renders both pages into images, lays them on top of each other in difference blending mode and counts how many pixels disagree. That catches things text can never see: a shifted margin, a swapped logo, a font substitution, a table that grew a row. Neither mode is a substitute for the other, and the usual working order is text first, then visual on the pages where the numbers look right but something still feels off.

Documents that do not match page for page

Pages are lined up by index, so page four is compared with page four. When one file has more pages, the extras are not an error: they are marked as whole pages added or removed, and the comparison carries on. Comparing a ten-page draft with a five-hundred-page final gives you a count of both and a clear note about which side the surplus sits on, rather than a refusal.

Where your files are processed

Both PDFs are opened, read and compared by your own browser. Neither one is uploaded, queued on a server or stored anywhere we can reach, and the report is built in the same tab. There is no account and no email step. Close the tab and both documents are gone from memory with them.

Frequently asked questions

When should I use visual mode instead of text mode?

Use text mode when you need to know which words changed and want to quote them. Use visual mode when the words are identical but the pages look different, or when one of the files is a scan and there are no words to read at all.

Do my files go to a server?

No. Reading both documents, extracting the text, running the comparison and writing the report all happen inside this browser tab. Two versions of an unsigned contract stay as private as the device they are sitting on.

What if one of the files is a scan with no text?

Text mode will tell you rather than pretend: a page image contains no words to compare. Either switch to visual mode, which works on any PDF, or run the scan through OCR first to give it a text layer and then compare properly.

How are documents with different page counts compared?

Page by index: the first page against the first, the second against the second. Extra pages on either side are reported as added or removed in full, and a note tells you how many pages each document has so the mismatch is never a surprise.

Why does visual mode find changes where the text matches?

Because pixels see more than words. A different font, tighter kerning, a re-exported image, a shifted margin or a page recompressed by another program all move pixels without touching a single character. That is the kind of change text comparison is blind to.

What does a pixel threshold of 12 out of 255 mean?

Two renderings of the same page never match exactly: anti-aliasing shifts brightness by a level or two. A pixel counts as different only when a colour channel moves by more than the threshold, so 12 ignores rendering noise while still catching real edits.

What is in the PDF report?

A header with the two file names and the totals, then one section per changed page listing every added and removed passage, tinted green and red. In visual mode it also lists the share of differing pixels for each page.