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


DiffPDF is a Windows graphical user interface (GUI) program for comparing two PDF files.

DiffPDF shows pairs of pages from the two PDFs being compared with any differences highlighted. Comparisons can be made based on the text regardless of layout, or based on appearance (which accounts for fonts, colors, layout, diagrams, images, etc.)

"Your software is the best I've ever used for comparing PDFs.",
—Customer comments on DiffPDF/DiffPDFc

DiffPDF is useful for anyone who needs to compare PDF documents, 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 command line tool, use our DiffPDFc program instead.)

Try or Buy

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 $140 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.

DiffPDF runs on all modern versions of Windows (XP, Vista, 7, and 8) whether 32-bit or 64-bit (on x86-compatible processors, i.e., most desktop and laptop computers).

  1. Download the DiffPDF installer DiffPDF-5.1.2-win32.msi (21 MB; MD5 82bf11d9ecaf868eb3c11a1059d4e000).
    (You may get an invalid warning about the .msi file—we have asked Microsoft to fix this. Also, some virus checkers may give a false positive, in which case use the .zip version.)
    Alternatively, download DiffPDF-5.1.2.zip (20MB; MD5 dc9556a8a67a5cf75949e3e43f00be5f).
  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. DiffPDF can be used once a license key has been registered.
    1. Start (i.e., double-click) DiffPDF, and if no license key has been registered or if a trial has expired it will show the Register window.
      Or, if you want to buy, click the Register button to pop up the Register window.
    2. Click either the Free Trial button or the Buy Now button to open a web browser window.
      • For a Free trial, enter the Computer ID (as shown in the Register window) into the web form, and click the Issue License Key button. Then copy the license key shown by the web form and paste it into the Register window's Key line edit and click OK.
      • To buy, complete the purchase on the secure MyCommerce website and then go to the Get Key page. Here, enter the Order ID (as shown on the payment confirmation page and email) and the Computer ID (as shown in the Register window) into the web form, and click the Get Key button. Then copy the license key shown by the web form and paste it into the Register window's Key line edit 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.

If you buy more than ten licenses it is possible to remotely deploy DiffPDF without the need for users installing or registering themselves. Contact support@qtrac.eu for details. (Enterprise-wide licenses are available for those requiring 10,000+ licenses.)

The manual can be viewed when the program is running by clicking the Help button then the Help menu option (providing you have a PDF viewer such as acroread installed). The manual is installed alongside the software (usually in "Program Files (x86)\Qtrac\DiffPDF\doc). You can also view the manual online at: DiffPDF-5.pdf (~1.2 MB). The license is available at diffpdf-license.pdf (27 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.


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


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 (such as the CSV report shown below). Nor do the screenshots reveal all the options that are available. For example, it is possible to exclude corners and/or margins 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 Text Report (CSV format)


By default, two decimal places are used for coordinates, but this can be changed to suit. DiffPDF can also output text reports in JSON and XML formats.

Note that when DiffPDF is told to do appearance comparisons, the textual reports indicate the square areas that differ (with a customizable square size).

Old Versions

We always recommend using the most recent release. These are kept available for those who want to use specific previous versions. (For details of the changes between versions, see the Changes page.)