Notepad++ can’t diff two files by itself. The ComparePlus plugin fills that gap. Install it through Plugins Admin, then open both files in tabs and run Plugins > ComparePlus > Compare. You get a side-by-side view with added, removed, changed and moved lines marked.
Developers use it on config files and source code. Everyone else tends to reach for it with logs, or with drafts that exist in two versions.
Plenty of tutorials still teach the original Compare plugin and its Alt+D shortcut. Its maintainer, pnedev, no longer supports it, and the ComparePlus Help page confirms the shortcut was removed.
Does comparing two files in Notepad++ need a plugin?
Yes. The editor has no diff feature, so the highlighting comes from a plugin, and on any current version ComparePlus is the one to install.
| Method | Highlights differences | Notepad++ version | Status |
|---|---|---|---|
| Split view, no plugin | No | Any | Built in |
| Compare plugin v2.0.x | Yes | v2.0.2 above 8.2.2, v2.0.1 below | No longer supported |
| ComparePlus | Yes | 8.4.2 or newer | Current, v3.0.0 in May 2026 |
What Notepad++ does without a plugin
The manual route puts two files side by side and leaves the reading to you. Right-click a tab and pick Move to Other View, then turn on View > Synchronize Vertical Scrolling and go through both panes line by line.
Nothing gets highlighted. Guiding Tech’s own walkthrough of this route calls skimming two large files tricky.
Compare plugin versus ComparePlus
Ty Landercasper created the original Compare plugin, and Jean-Sebastien Leroy later maintained it. pnedev built ComparePlus from its latest development state and shipped v1.0.0 on 1 September 2022 (ComparePlus release notes).
The ComparePlus README now says the older plugin gets no further support from its maintainer. Many tutorials still teach it anyway.
On Notepad++ 8.4.2 or newer, install ComparePlus. On anything older, Compare v2.0.2 works above 8.2.2 and v2.0.1 covers 7.7 to 8.2.2.
Honestly, updating Notepad++ beats running an unsupported plugin. That’s the simpler fix.
One catch on the version floor. The README lists 8.4.2 as supported, yet a community test of ComparePlus 1.2.0 on 8.4.2 raised a marker allocation error asking for 8.5.6 or newer (Notepad++ community thread).
How to install ComparePlus in Notepad++
Open Plugins > Plugins Admin, tick ComparePlus in the Available tab, click Install and let Notepad++ restart. When Plugins Admin cannot reach GitHub, copying the release zip into a ComparePlus plugin folder gives the same result.
Install through Plugins Admin
Search for “Compare” in the Available tab, tick the box next to ComparePlus and press Install.
Notepad++ closes and reopens to finish the job, and Windows asks for administrator approval when the editor sits in Program Files. Afterwards ComparePlus shows up in the Installed tab and in the Plugins menu.
Read the name before ticking. Plugins Admin has listed both Compare and ComparePlus side by side (Notepad++ community thread), and the old one is the unsupported one.
Install manually from a GitHub release
- Open ? > Debug Info and read the 32-bit or 64-bit tag, then download the matching x86, x64 or ARM64 zip from the pnedev/comparePlus releases page.
- Create a ComparePlus folder inside the Notepad++ plugins folder.
- Copy ComparePlus.dll into it, along with the libs sub-folder, which holds the Git and SQLite libraries.
- Close every Notepad++ window and reopen it.
The folder name matters. A DLL dropped loose into the plugins directory never loads, which is one reason the menu stays empty after a manual copy (Notepad++ User Manual).
ARM64 users lose one command. The v1.0.0 release notes say that build has no SVN diff, because the SVN library has no ARM64 variant.
How to compare two files in Notepad++ side by side
With both files open in tabs and the newer one active, run Plugins > ComparePlus > Compare. The view splits and every difference gets a margin symbol and a color.
- Open both files in separate tabs (File > Open, or drag them into the window).
- Click the tab of the newer file.
- Choose Plugins > ComparePlus > Compare. Skip the Alt+D shortcut older tutorials mention, since it no longer exists (see the shortcut section below).
- Read the result. The new file sits in the right view by default, the old one on the left.
- Edit either file and save. With Re-Compare active on Save checked in Settings, the result refreshes after each save.
- Finish with Clear Active Compare for the current pair, or Clear All Compares to drop every active pair.
Which file the plugin treats as new
ComparePlus assumes you compare an old version of your work with its new version, and it calls the new file the focal file (ComparePlus Help page). The plus and minus symbols only make sense once you know which side is which.
Set as First to Compare lets you mark the old file, then you activate the new one and press Compare. With just two files open, Compare checks the second against the first. When many files are open, move one tab across with Move to Other View and compare from there. The moved file counts as new by default.
Two Settings entries change that. The one named First is decides whether the file marked with Set as First counts as old or new, and Old file position swaps the sides.
Starting a comparison from the command line
The command is notepad++ -pluginMessage=compare new_file.txt old_file.txt, and it starts the comparison on launch.
The v1.1.0 release notes put the new file first, while the v1.0.0 notes listed the old file first. Test with a throwaway pair before scripting it, since v2.2.0 (November 2025) fixed several command line triggering issues.
How to read the highlighted differences and move between them
ComparePlus marks each differing line with a margin symbol and a background color, and every line state looks different from the others.
Added lines exist only in the new file and get a plus. Removed lines exist only in the old one and get a minus (ComparePlus Help page). Changed lines mostly match, with edits inside them. A moved line appears once in the other file, at a different position, while a moved-multiple line shows up there several times at different positions.
What switching off Detect Moves does
With Detect Moves unchecked, a plus means the line is missing at that location in the old file, even if it exists elsewhere. A reordered block then reads as one removal and one addition instead of a move.
Jumping between differences
Next and Previous commands jump from one difference to the next, and the navigation bar gives a map of the whole file. Both views scroll together while a comparison is active, and v2.0.0 (August 2025) cut the scroll lag.
Wrap around diffs makes Next loop from the last difference back to the first, and Go to first diff after re-Compare decides whether the caret resets. Diffs visual filtering, added in v2.0.0, hides every difference type you do not pick.
Shortcut keys
Several tutorials still list Alt+D as the compare shortcut. The ComparePlus Help page says it was removed because Alt plus a letter opens a Windows menu.
Assign your own keys under Settings > Shortcut Mapper > Plugin Commands, for Compare, Next and Previous.
Comparison options that change the result
ComparePlus gathers its detect and ignore switches in one compare options dialog, added in v2.0.0. Start with every option off and enable only the ones you can name a reason for.
Ignore options
Spaces and blank lines can be ignored, and so can letter case, each with its own switch. The old Ignore Space option became Ignore All Spaces in v1.2.0, when Ignore Changed Spaces joined it.
Line endings count too. Since v2.0.0 the comparison includes EOL, so a CRLF file against an LF file shows differences until the EOL ignore option is on.
Folded lines can be excluded (since v1.2.0) and hidden lines as well (since v2.0.0).
The regex option ignores the portions of each line that match a pattern, or compares only the matching portions (Boost Regex engine, v2.0.0). Two log exports that differ only by timestamps are the textbook case for it. A pattern such as ^\d{4}-\d\d-\d\d \d\d:\d\d:\d\d leaves only the real differences.
Keep the whitespace options off for YAML and Python, and for Makefiles too, since indentation is content there. When two files match only because of ignored differences, the plugin says so (v2.0.0 notes).
Character diffs and sub-line moves
Changed lines get character-level marks, so one swapped digit stands out in a long line. v2.0.0 added a switch to disable changed lines detection and another to detect moves inside a changed line.
My rule of thumb is to keep character marks on for config files and source code, where one digit matters, and to turn changed lines detection off for prose that was rewritten wholesale.
Comparing selections and finding unique lines
Compare Selected Lines checks only the highlighted blocks in each file (ComparePlus Help page). The Find Unique commands list lines present in only one file or selection (v1.0.0 notes), and several compared pairs can stay active at once (README).
Selections beat a full-file compare when two documents share one section and nothing else.
Comparing against Git, SVN, the last saved version or the clipboard
Besides a second open file, ComparePlus can compare the active file against its last saved version, Git, SVN or the clipboard.
| Base | Command | Needs | Good for |
|---|---|---|---|
| Last saved version | Diff since last Save | Unsaved edits in the active file | Reviewing your own edits |
| Git | SVN/Git Diff | File inside a repository, libgit2 | Checking a change against the repository copy |
| SVN | SVN/Git Diff | File inside a repository, SQLite | Same check on SVN projects |
| Clipboard | Clipboard diff command | Copied text | Two snippets, no saved files |
Diff since last Save only has something to show while the buffer holds unsaved changes, because it compares the modified file with its contents on disk (ComparePlus Help page).
For two pasted text blocks, paste one into a tab, copy the other and run the clipboard comparison. Neither block needs a saved file, according to the README.
Why the compare plugin does not show up or fails in Notepad++
Most reports in Notepad++ community threads and ComparePlus release notes come down to a Plugins Admin list out of step with the editor, a crash under one rendering mode, mismatched line endings or encodings, and very large files.
When ComparePlus is missing from every Plugins Admin tab, notepad++.exe and nppPluginList.dll can come from different builds. The dialog shows a Plugin list version in its lower right corner, and Notepad++ 8.4.6 should carry 1.5.4. pnedev suggested a full uninstall and clean reinstall of that version. PeterJones offered a lighter route, which is to overwrite nppPluginList.dll in the plugins\Config folder with the copy from the matching portable package.
If the whole file is flagged as changed, look at line endings first. They count in the comparison since v2.0.0, so either turn on the EOL ignore option or convert one file under Edit > EOL Conversion.
An encoding warning on compare comes from the Warn about encodings mismatch setting, and the Help page says results can be inaccurate when encodings differ. Convert both files to one encoding from the Encoding menu first.
Notepad++ closes when you click Compare
The v2.2.0 release notes list a known issue where Notepad++ closes on compare under the DirectWrite on GDI DC rendering mode, in every ComparePlus version after 1.2.0.
A May 2026 community thread shows it on Notepad++ 8.9.4 with ComparePlus 2.2. Every click on Compare closed the editor while two XML files were open, and DirectWrite is the default rendering mode there.
pnedev’s workaround is to set the rendering mode to GDI under Settings > Preferences > MISC, restart, and compare again. ComparePlus v3.0.0, released in May 2026, lists a fix for a crash on DirectWrite rendering.
Large files
Compare plugin v2.0.2 handles files above 2 GB in 64-bit builds, following the Scintilla changes in Notepad++ 8.2.2 (pnedev release notes).
v1.2.0 added a warning before comparing very large files, and it stopped auto re-compare when a compare took more than 5 seconds. v3.0.0 dropped that warning and reworked the comparison with a Histogram approach, for accuracy and speed. The ComparePlus release notes state no maximum file size.
Test a trimmed copy first when the inputs run into gigabytes.
When a standalone diff tool is the better choice
Stay with ComparePlus for two text files. Switch when the job involves a folder or a three-way merge, or when you need a byte-level check.
ComparePlus works on file pairs, selections, the clipboard, Git and SVN, and its README lists no folder comparison. Every external tool also costs a detour. Both files must be saved to disk and opened in another application.
WinMerge
WinMerge is an open source differencing and merging tool for Windows (winmerge.org). It compares folders as well as files, including 3-way folder comparison, and it does 3-way file comparison and moved lines detection too. It reads Windows, Unix and Mac text formats.
The downsides are that it only runs on Windows and opens a separate window for a job ComparePlus already does.
Beyond Compare
Scooter Software sells it as a commercial product for Windows, macOS and Linux. Per the company’s product description it handles file and folder comparison, folder sync, and has dedicated viewers for binary data and images.
It costs money, and three-way merge is limited to the Pro edition.
Meld and KDiff3
Meld is a free GNOME project (GPL-2.0-or-later) that compares two or three files or directories and supports Git and Subversion working copies. KDiff3 comes from KDE, is open source, compares and merges two or three files or folders, and marks differences character by character (KDiff3 Handbook).
Both mean another application to learn, and neither beats ComparePlus on a plain two-file check.
The fc command
Windows ships fc, which compares two files from the command prompt. Run fc /b old.bin new.bin for a byte-by-byte comparison, or fc /c old.txt new.txt to ignore letter case.
By default fc cancels the comparison when more than 100 consecutive lines differ, because its internal line buffer holds 100 lines (Microsoft Learn).
Nothing needs installing, and there’s a binary mode. Exit code 0 means identical files and 1 means different ones, which suits scripts. The output is console only, though, and PowerShell needs fc.exe typed in full because fc is an alias for Format-Custom there.
FAQ About Comparing Two Files in Notepad++
Can Notepad++ compare two folders?
No. ComparePlus works on file pairs, selections, the clipboard, Git and SVN, and its README lists no folder comparison.
WinMerge, Meld, KDiff3 and Beyond Compare all compare directories.
Is ComparePlus free to use?
Yes. The plugin is released under the GPL-3.0 license and costs nothing.
The author accepts donations through a link on the ComparePlus Help page.
Can Compare and ComparePlus stay installed together?
The ComparePlus README describes no conflict between them, but the original plugin is unsupported.
Remove it once ComparePlus works, so the Plugins menu holds one comparison tool.
How do I update ComparePlus?
Open Plugins > Plugins Admin, switch to the Updates tab, tick ComparePlus and click Update.
After a manual install, copy the contents of the new release zip over the existing ComparePlus folder and restart Notepad++.
Does ComparePlus compare binary files?
The README lists no binary mode, so treat it as a text tool.
For byte-level checks, fc /b compares two files byte by byte, and Beyond Compare ships a viewer for binary data.
Can I compare files in Notepad++ on Mac or Linux?
No. Notepad++ has no official Mac or Linux build, so the plugin stays on Windows with it.
KDiff3 and Beyond Compare ship Linux and macOS builds, and Meld runs on Linux, with macOS available through Homebrew or unofficial builds.
Merging the Differences Back Into One File
ComparePlus can merge the differences without a second tool. Left-click a difference’s margin symbol to equalize it, or generate a patch from the comparison and apply it to the old file.
Copy the old file before anything else. Then switch every ignore option off, save, and re-compare.
That order follows a documented limit. Reverting a patch can fail when the comparison ran with ignore options on, because the patch context no longer matches (ComparePlus v2.0.0 notes). A backup copy of the old file is the fallback when that happens.
With ignore options off, a Files Match message means the two files are identical. With them on, the plugin reports the ignored differences that remain, as of ComparePlus v2.0.0 in August 2025.
- Protecting Users and Brand Standards Across Image-Driven Platforms - November 10, 2026
- Go Cheat Sheet - November 9, 2026
- Build or White-Label Software? How Software Teams Decide What to Resell in 2026 - November 9, 2026
