DiffPDF DiffPDF screenshot DiffPDF is an easy to use commercial Windows application for PDF comparison, ideal for office workers. It has many customizable features. Comparisons are done on your own computer to protect your privacy. DiffPDF icon 180 Software Qtrac Ltd. OnlineOnly 300988032
Qtrac Ltd.


DiffPDF is used to compare two PDF files—textually or visually.


Use DiffPDF to compare PDF files quickly and easily:
Click to choose one PDF; click to choose another PDF; click Compare.
The changes are shown as if you'd used highlighter pens to show added, changed, or deleted text.

This Windows application is our easiest to use and most affordable and popular product. Some customers report it as superior in functionality and far faster than Adobe Acrobat's Diff tool.Your PDFs are safely compared on your own computer without the size or page limits of online tools. (See also Why Compare PDFs?)

Comparisons can be made based on the text regardless of layout, or based on appearance (which accounts for fonts, colors, layout, diagrams, images, etc.)

DiffPDF is useful for anyone who needs to compare PDFs, reports, books, or labels—for example, archivists, engineers, journalists, packagers, publishers, researchers, software testers, and translators. DiffPDF is used in a wide range of contexts, from book authors to banks, insurance companies, and Government. (Screenshots.)

If you require a console-based command line tool, use com­pare­pdf­cmd.

"Your software is the best I've ever used for comparing PDFs.", —customer feedback.

Legal copies of our software are only available from www.qtrac.eu, www.qtrac.uk, www.diffpdf.com, and diffpdf.appspot.com, and can only be bought via MyCommerce/ShareIT.

Try (free for 20 days) or Buy ($180 USD)

Try (free for 20 days)

You can try DiffPDF free for up to 20 days using a trial license key. And you can buy a full license key for DiffPDF that has no time limit for $180 USD plus local sales tax (or local equivalent for many major currencies) using the secure MyCommerce platform. Tiered price discounts are applied if you buy at least 10 license keys—these are shown when you click Buy Now. (Purchasing departments: DiffPDF's Product ID is 300988032.)

DiffPDF 6 is a 64-bit application that will work only on 64-bit Windows.

Note that DiffPDF 5 license keys are not valid for DiffPDF 6. So if you have a DiffPDF 5 license, or require a 32-bit application, you will need to use DiffPDF 5 instead.

  1. On the computer you want to use, either:
  2. Double-click the installer and follow the on-screen instructions to install DiffPDF.
    (Alternatively, unpack the .zip file and create a shortcut to DiffPDF.exe.)
  3. The first time DiffPDF is run it will automatically try to acquire a free trial license key over the internet, after which it will be ready for use.

Buy ($180 USD)

Once you're ready to buy DiffPDF, start it up, then click the Register button to show the Register window, then:

  1. Click the Register window's Buy Now button to open a web browser window at the secure MyCommerce purchase page, and complete the purchase.
  2. Now go to the 'get key' page whose link will be emailed to you with the Order ID.
  3. In the 'get key' page, the Order ID will be shown. (If not, you can copy it from the payment confirmation page or the confirmation email).
  4. Open the file C:\Users\<username>\AppData\Local\Temp\cid.txt and copy the Computer ID that's in this file (and the same as shown in the Register window) to the clipboard.
  5. Paste the Computer ID into the web form—or if you didn't copy it to the clipboard, type it carefully from the Register window—and click the web form's Get Key button.
  6. Copy the license key shown on the web form and paste it into the Register window's Key line edit, check the checkbox, and click OK.

If your security settings prevent the buttons from working, use one of these links: Free Trial or Buy Now.

We recommend trying before buying, since license key purchases can't be refunded.

Note that each individual license key is tied to the particular computer it is acquired on. Each license key is valid for all minor and patch versions (e.g., if acquired for version 6, it is valid for all 6.x.y versions). There is no time limit for full license keys—providing the firmware and hardware (and how Windows reports it)—don't change.

The manual can be viewed when the program is running by clicking the Help button then the Help menu option. You can also view the manual online at: DiffPDF-6.pdf (764 KB). The license is available at diffpdf6-license.pdf (28 KB) and from within the program.


The first screenshot shows how easy DiffPDF is to use: choose the two PDFs to compare, then click the Compare button. (Top)

Image diffpdf6-main1_M1.pngImage diffpdf6-main1_M2.pngImage diffpdf6-main1_M3.png

By default DiffPDF highlights deleted text in red, inserted text in cyan, and replaced text in magenta. All the colors can be customized, or plain highlighting can be chosen. The change bar color, thickness, and indent can also be customized—or the change bar can be hidden entirely. (Top)

Image diffpdf6-main2_M1.pngImage diffpdf6-main2_M2.png

In this screenshot we see that the control panel can be switched to the right, and the view panels can be set to be vertical—useful for PDFs that are much wider than they are tall. (All four possible layout options are supported.)

What the screenshots don't show is that DiffPDF can produce reports—either a PDF that matches what's seen on the screen, or textual reports. Nor do the screenshots reveal all the options that are available. For example, it is possible to exclude corners and/or margins and/or arbitrary rectangles from consideration when comparing, which is ideal for excluding timestamps. It is also possible to compare ranges of pages to account for inserted and deleted pages. All DiffPDF's functionality is explained in the manual, and, of course, you can try it before buying it.

Example Comparison

Here is an example comparison that shows how DiffPDF indicates differences between two PDFs whose pages are slightly different:

Image report-2_M1.pngImage report-2_M2.pngImage report-2_M3.png

By default, change bars are shown in red, and changes are highlighted with deletions in red, insertions in cyan, and replacements in magenta. In this example, the red and cyan highlighting indicates text that has moved (i.e., been deleted from one place and inserted in another). And the magenta highlighting indicates text that has been replaced in its original position. (Note that if plain rather than change highlighting is used—which is the default—all differences are shown in yellow.) All colors can be changed, as can the width of the change bar and many other things.

The image above shows what appears on-screen in DiffPDF's user interface. DiffPDF can also output PDF reports which contain each pair of differing pages with the differences highlighted as shown above.

Previous Version

We always recommend using the most recent release. (For details of the changes between versions, see the Changes page.) We will provide earlier versions to customers on request.