DiffPDF DiffPDF screenshot DiffPDF is an easy to use commercial Windows GUI application for comparing PDF files, ideal for office workers. It has many customizable features. Comparisons are done on your own computer to protect your privacy. Qtrac Ltd. 150 Software Qtrac Ltd.


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


Use DiffPDF to compare PDF files quickly and easily:
Click or drag one PDF; click or drag another PDF; click Compare.

DiffPDF is a commercial Windows graphical user interface (GUI) application ideal for office workers. (See also Why Compare PDFs?)

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.) DiffPDF is cloud-free: it runs on your own computer without the size or page limits of online tools—some customers compare PDFs with thousands of pages.

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 console-based command line tool, use comparepdfcmd.

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

Try (free for 20 days) or Buy ($160 USD)

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 $160 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 300907067.)

DiffPDF is available as a 32-bit application (-win32) that will work on modern 32-bit and 64-bit Windows, and as a 64-bit application (-amd64) that will work only on 64-bit Windows. (In both cases the computer must have an x86-compatible processor, i.e., almost all desktop and laptop computers.)

  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. DiffPDF can be used once a license key has been registered.
    1. Start (i.e., double-click) DiffPDF.
    2. Once DiffPDF has started, 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.
    3. Click either the Free Trial button or the Buy Now button to open a web browser window.
      • For a Free trial the Computer ID should appear in the web page. (If it doesn't, then click in the Register window to copy the Computer ID to the clipboard, then paste it into the web form.)
        Click the web form's 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, check the checkbox, and click OK.
      • To buy, first complete the purchase on the secure MyCommerce website.
        Then go to the 'get key' page whose link will be emailed to you with the Order ID.
        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).
        Click in the Register window to copy the Computer ID to the clipboard.
        Paste the Computer ID into the web form, and click the web form's Get Key button.
        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 5, it is valid for all 5.x.y versions), and may be used with 32-bit or 64-bit editions. There is no time limit for full license keys—providing the 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 (providing you have a PDF viewer 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 (961 KB). The license is available at diffpdf-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 diffpdf5_M1.pngImage diffpdf5_M2.pngImage diffpdf5_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 diffpdf5-right_M1.pngImage diffpdf5-right_M2.pngImage diffpdf5-right_M3.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.

Old Versions

We always recommend using the most recent release. Old versions are kept available for those who want to use specific previous versions. We normally only provide the highest patch release of any given minor release. (For details of the changes between versions, see the Changes page.)