What does Identical mean?

Identical means the bytes that were compared matched. If only samples were read, the result still says identical but is not fully verified. Probable means contents were not read at all. Errors and ignored files are never called identical.

Can I compare a Word file with a PDF?

Yes. Word (.docx), OpenDocument text (.odt), RTF and PDF are recognized by content, not only by name. Any two of those can be compared as text, as Word-style markup, or as side-by-side pages.

What happens after three months?

Every feature is included for three months. After that, Markup and Pages (the Word-style combined view and side-by-side document pages) need a licence at 15 US dollars per year. Folder, text, semantic and image comparison stay available.

DiffMan

Q: Does DiffMan upload my files?

No. Comparison runs entirely on your Mac. Folders, documents and images are not sent to any website. You do not need an internet connection to compare. If the Mac is online, DiffMan may send four anonymous counters (install, open, first compare, session count) with no paths and no file contents. Comparison does not wait for that send and works when it fails.

A completely free tool to compare any two files, folders, images, or documents right on your computer.

Markup view of a contract: deleted words in red with strikethrough, inserted words in green with underline

Pages view: original contract on the left, revised contract on the right, changed words marked, preview strip on the right

Folder comparison: two trees with identical, different, left-only and right-only files, plus a count of each

Side-by-side XML files with removed lines in red, added lines in green, and a minimap on the right

Two beach illustrations side by side with orange boxes around pixels that differ

Difference image: changed pixels in red on a faded copy of the left picture

What it does

Pick two folders or two files. Browse, drop them on a side, or pass them on the command line. DiffMan reports what is the same, what differs, and what exists on only one side. Double-click a file in a folder result to open the matching viewer.

Folder comparison

A tree of every item: identical, different, left only, right only, probable, ignored, errors. Copy a file or folder to the other side only when you confirm it.

How folder compare works

Text diff and editing

Two panes you can edit. Removed lines are red, added lines are green, replaced lines are blue, and changed words inside a line are marked. Save keeps encoding and line endings.

Text comparison

JSON, XML and the rest

JSON, YAML, TOML, XML, INI and Java properties can be compared by meaning. Keys are sorted, comments dropped, then the canonical text is diffed. If a file does not parse, you get lines and a reason.

Semantic comparison

Word, ODT, RTF and PDF

Read the text, see a Word-style markup page, or look at both documents page by page. A Word file against a PDF is a valid pair. After three months, markup and pages need a licence.

Document comparison

Image comparison

Side by side, overlay, or a difference image. Exact pixels, or a tolerance that groups nearby changes into regions you can step through.

Image comparison

Settings

How files are sampled, what Identical means, ignore rules, text font and whitespace, image tolerance. Each switch is documented.

Settings in detail

Built so the result can be trusted

Local, not a web service. Files never leave you computer. Comparison does not need the internet. See Your files stay on you computer.
No silent writes. Comparison never changes files. A copy needs a confirmation. Save writes the pane that has the cursor, and only after checking the file did not change on disk.
Identical is earned. A quick sample that matches is still identical, and the window says it is not fully verified. Probable means the contents were not read. Unreadable and ignored items are never identical.
A different size is different content. A different modification time is not. Timestamp gaps are shown separately unless you turn that off.
Limits are stated. Password-protected PDFs, files over 4 MB of text, scans with no text layer, images of different sizes: you get a reason, not an empty pane pretending to be a result.

Licence in short

The first three months include every feature. After that, folder comparison, text, semantic compare and images stay available. The Word-style markup view and the side-by-side document pages need a licence: $15 USD per year. Checkout is not live yet; the licence page is the planned offer.

From the command line

Pass two paths after the app name, for example DiffMan ./left ./right or DiffMan a.txt b.txt. Relative paths use the working directory. The app is sandboxed, so it can read only paths macOS has already allowed; otherwise use Browse or drop the items.

DiffMan ./left ./right
DiffMan contract-v1.docx contract-v2.pdf

Questions

Does DiffMan upload my files? Does it need the internet?

No, and no. Comparison runs on your Mac. Folders, Word files, PDFs and images are not sent anywhere. You can compare with Wi-Fi off. If the Mac is online, DiffMan may send four anonymous counters (install, open, first compare, session count) with no paths and no contents. That send is not part of the comparison. If it fails, nothing about your files is affected.

What is the difference between Identical and Probable?

Identical means the bytes that were compared matched. If sampling is on and the samples match, that is still Identical, with a note that the rest of the file was not read. Turn on full byte-for-byte verification to compare every byte. Probable means no content check ran, for example when a timestamp change skips the read.

Can I compare Word with PDF, or ODT with RTF?

Yes. Those four formats are recognized by content. Any two can be opened as a document pair: text, markup, or pages.

Download

Download DiffMan for Mac Download DiffMan for Windows