Notepad++ can’t compare files on its own. You install the ComparePlus plugin, open both files in separate tabs, and run Plugins > ComparePlus > Compare. The plugin splits the window into two panels and marks lines that were added, removed, changed or moved.
Your Notepad++ build matters here. ComparePlus needs 8.4.2 or later, and it exists because the older Compare plugin lost its maintainer’s support (ComparePlus README, GitHub). Plugins Admin offers v3.0.0 only on 8.4.7 or later. Anyone on 8.4.2 to 8.4.6 gets ComparePlus v1.0.0 instead (Notepad++ Plugin List).
One more thing before you start. Plenty of old tutorials tell you to press Alt+D. That shortcut is gone. The plugin’s Help file says it was dropped because it clashed with the Windows habit of Alt+letter opening a menu.
Which plugin do you need to compare files in Notepad++?
ComparePlus, unless your build is too old for it. Plugins Admin lists it next to the original Compare, which is credited to Ty Landercasper, Jean-Sebastien Leroy and Pavel Nedev. ComparePlus is by Pavel Nedev alone, and the README on GitHub says it is meant to replace Compare, since Compare is no longer supported by its maintainer.
| Option | Works with | Status | Diff features |
|---|---|---|---|
| ComparePlus | Notepad++ 8.4.2 and later (v3.0.0 needs 8.4.7 and later) | Maintained | Highlights, selections, last save, clipboard, Git, SVN |
| Compare | Notepad++ 7.7 and later | No longer supported | Side by side diff, Git and SVN diff |
| No plugin | Any version | Built in | Twin view, no highlighting |
The old Compare only makes sense if you’re stuck below 8.4.2 and can’t upgrade. Everybody else should skip it.
The newest ComparePlus release notes entry is v3.0.0, dated 18 May 2026. It rebuilt the diff on a histogram approach, which the notes credit with better accuracy and speed. Keep in mind that Plugins Admin installs whatever version the Plugin List records (Notepad++ User Manual), and that isn’t always the latest GitHub release.
How to install the comparison plugin
Open Plugins > Plugins Admin and find ComparePlus in the Available tab.
- Start Notepad++ and go to Plugins > Plugins Admin.
- Tick the checkbox next to ComparePlus. Clicking only the name shows plugin info and leaves the Install button greyed out (Notepad++ User Manual).
- Click Install and accept the restart.
- Check the Installed tab, then look for ComparePlus in the Plugins menu.
You don’t have to pick between x86, x64 and ARM64 yourself. The Plugin List keeps a separate file for each, and Plugins Admin grabs the one that fits your Notepad++.
When Plugins Admin doesn’t list the plugin, go manual. Download the release zip for your build (x86, x64 or ARM64) from the ComparePlus GitHub releases, create a ComparePlus folder inside the Notepad++ plugins folder, and copy the zip contents in. Leave the libs sub-folder alone. It holds the libgit2 and SQLite libraries the Git and SVN commands rely on. Restart Notepad++ afterwards.
If the plugin does not show up
Forum threads on this keep landing on the same few causes.
- The Notepad++ build is too old. ComparePlus wants 8.4.2 or later, and v3.0.0 wants 8.4.7 or later. Plugins that no longer fit the installed build end up in the Incompatible tab of Plugins Admin (Notepad++ User Manual).
- The architecture doesn’t match. A 32-bit plugin loaded into 64-bit Notepad++ throws a “Cannot load 32-bit plugin” error, as users report on the Notepad++ Community forum. A corrupt or unreadable DLL can produce the same message.
- The DLL sits directly in the plugins folder. It won’t load from there. It needs its own subfolder, named exactly like the DLL without the extension.
- Windows blocked the download. DLLs from the internet stay blocked until you tick Unblock in the file’s Properties.
No write access to the program folder? Restart Notepad++ with Run as administrator before installing.
Plugins Admin can also report the package as not found (a forum user hit this on v8.6.7). The manual route above is the way around it.
How to compare two files step by step
Open both files, each in its own tab, either through File > Open or by dragging them into the window. If more than two tabs are open, mark the old file first with Set as First to Compare. Then run Plugins > ComparePlus > Compare.
Two panels appear with every difference marked, and the new file sits on the right by default. To close the comparison, use Clear Active Compare. With several pairs open, Clear All Compares wipes the lot.
Identical files give you a “Files Match” message. Since v2.0.0 (August 2025), ComparePlus also tells you when an ignore option hid differences in files it considers matching (ComparePlus release notes).
Which file counts as the new one
The file you compare from is the new, focal one, and ComparePlus checks it against the old file (ComparePlus Help file). With two files open, that’s simply the active tab.
With more tabs, it gets fiddly. Activate the old file, run Set as First to Compare, switch to the new file, then hit Compare. Moving a tab to the other view works too: right-click it, choose Move to Other View, and Compare pairs it with the file already sitting in that view.
The First is and Old file position settings flip the default layout. And if the two files use different encodings you get a warning, because the results may be off.
The Alt+D shortcut and custom shortcuts
Several tutorials still give Alt+D as the Compare shortcut. According to the ComparePlus Help file it was removed over the Alt+letter menu clash on Windows.
Set your own key under Settings > Shortcut Mapper > Plugin Commands. Until you do, the Plugins menu path is the one that always works.
How to read and step through the differences
A plus sign in the margin means the line exists only in the new file, and a minus sign means it exists only in the old one. Each sign shows up only on the side that has the line. Changed lines and moved lines get their own colors.
What the margin markers mean
- A changed line matches mostly in both files, with edits inside it.
- A moved line appears once in the other file, at a different position.
- A moved-multiple line shows up several times in the other file, each at a different position.
Untick Detect Moves and the markers shift meaning. A line flagged as added may still be in the old file, only somewhere else (ComparePlus Help file).
How to jump between differences
Skip the scrolling. The plugin menu has Next, Previous, First and Last difference commands.
- Wrap around diffs makes Next loop from the last difference back to the first.
- Re-Compare active on Save refreshes the diff every time you save.
- Unticking Go to first diff after re-Compare keeps the caret where it was.
There’s also a navigation bar for the compared files, and the Compact Navigation Bar setting slims it down.
How the panels stay aligned
Both panels scroll together, and padding keeps matching lines level. ComparePlus does this with Scintilla annotations and keeps your undo history intact (ComparePlus release notes, v1.0.0, 2022).
Right-click the gripper between the panels and use the Rotate commands to flip between horizontal and vertical split. The Help file recommends restarting Notepad++ after switching.
Which comparison modes and options does ComparePlus add?
Beyond a plain file-versus-file diff, the README lists selections, unique lines, last save, clipboard, Git and SVN. Ignore options then decide what counts as a difference at all.
Comparison modes
Which mode you pick depends on what the file is being compared against.
- Selections mode compares only the blocks you highlight in each file, which suits a single function or one config section.
- Last save compares an edited, unsaved file with what was last written to disk.
- Clipboard compares a file or a selection with whatever text is on the clipboard, so you don’t need a second file.
- Unique lines lists lines that exist in only one file or selection.
- Git and SVN compare the file with its repository version. Git diff runs on libgit2, and SVN diff runs on sqlite.
My rule of thumb: last save while you’re editing, Git diff for tracked code, selection compare when only one block matters.
One catch. The v1.0.0 release notes (2022) say the ARM64 build ships without the SVN diff command, because the SQLite library it depends on had no ARM64 variant. Later notes don’t say whether that changed.
Comparison options
The ignore list has grown over time, first in v1.2.0 (February 2024) and again in v2.0.0 (August 2025).
- Ignore all spaces, or ignore only changed spaces (the second one joined in v1.2.0)
- Ignore empty lines
- Ignore letter case
- Ignore line endings (EOL)
- Ignore, or compare only, the line portions matching a regex (Boost Regex engine, since v2.0.0)
- Character diffs and moved-line detection, with sub-line moves added in v2.0.0
Since v2.0.0, line endings count as part of the comparison. Check a CRLF file against an LF copy and you can get line after line flagged until you tick the EOL ignore option (ComparePlus release notes).
A compare options dialog puts every detect and ignore switch in one place. A separate diffs visual filtering dialog hides the difference types you don’t care about.
How to compare files without a plugin
You can split the window into two views and read both panels by eye. Notepad++ shows the files side by side but marks nothing.
- Open both files, then send one to the other view with Move to Other View, or drag its tab across (Notepad++ User Manual).
- Turn on View > Synchronize Vertical Scrolling so both panels move together.
- Skip Clone to Other View. It mirrors one file in both views, which helps when you’re editing two spots of the same document and does nothing for two different files.
This is fine for short configs, a handful of changed lines, a quick visual check. It falls apart on long files, and on any pair where lines were inserted.
The scroll lock moves both views in the same direction (Notepad++ User Manual, Views). After an insertion the matching text stops lining up, and you end up re-aligning one panel by hand.
When Notepad++ is the wrong tool for comparing files
Switch tools when the job involves folders, three versions of one file, or files too large or too noisy for a line-by-line diff. The ComparePlus feature list stops at file pairs, selections, clipboard text, Git and SVN.
Limits that decide the switch
Folder-level comparison doesn’t appear anywhere in the feature list. The plugin also works in pairs, so a three-way merge needs something else.
The diff runs line by line and marks character changes inside changed lines. A reflowed paragraph therefore registers as a pile of changed lines.
Stability is worth a mention too. The v2.2.0 notes list a known issue where the DirectWrite on GDI DC rendering mode closes Notepad++ when you compare.
How large a file can Notepad++ compare?
Older Notepad++ Community threads put the ceiling at 2 GB, tied to a 32-bit integer size check in the file-open code. Notepad++ v8.3 (February 2022) removed the 2 GB open restriction for the 64-bit binary, and the Compare v2.0.2 release followed that Scintilla change (the Plugin List marks it for Notepad++ 8.3 and later).
So the two positions describe different builds. The forum figures predate 8.3, and a current 64-bit install isn’t held to the old cap.
ComparePlus changed its own large-file behavior over time. v1.2.0 (February 2024) added a warning before comparing very large files, and the same release switched off auto-recompare when a comparison took more than 5 seconds. Then v3.0.0 removed the file-size warning, so a slow comparison no longer announces itself in advance.
The v3.0.0 notes also list a fix for a DirectWrite crash. They don’t say whether it covers the GDI DC case from the v2.2.0 known issue.
Alternatives compared
| Tool | What it adds over ComparePlus | Pick it when |
|---|---|---|
| WinMerge | Folder comparison, 3-way file comparison | Directories or three file versions are involved |
| Beyond Compare | File and folder diff on Windows, macOS, Linux | One paid tool must cover several operating systems |
| Visual Studio Code | Diff editor and three-way merge from the command line | The file already lives in a VS Code project |
| fc command | Runs from any prompt, returns exit codes | A script needs a quick identical-or-different answer |
WinMerge is free, open source and built for Windows, with regex-based file filters for folder compares (WinMerge project).
Beyond Compare costs money. As listed in November 2026, Scooter Software charges $35 for Standard and $70 for Pro per user at one to four licenses. Licenses are perpetual for a major version, and evaluation is free.
For Visual Studio Code, code --diff file1 file2 opens the diff editor, and --merge takes four paths for a three-way merge (VS Code documentation).
The fc command works line by line through a 100-line buffer. When it can’t realign inside that buffer it stops with “Resynch failed. Files are too different.” (Microsoft Learn). In PowerShell, type fc.exe, because fc is an alias for Format-Custom.
For two-file checks on text that’s already open, stay in Notepad++. WinMerge covers folders for free, so Beyond Compare earns its price mainly when macOS or Linux is in the mix.
Common Questions About File Comparison in Notepad++
Does comparing files change the files themselves?
Not in the default setup. ComparePlus aligns the panels with Scintilla annotations instead of inserted lines (ComparePlus release notes, v1.0.0).
The Help file describes blank-line padding as the old implementation, tied to the Align replacements setting.
Can several file pairs be compared at the same time?
Yes. The ComparePlus README says several compared file pairs can be active and displayed at once. Run Set as First to Compare and Compare separately for each pair.
Is ComparePlus free to use?
It is. ComparePlus is open source under the GPL-3.0 license, and its source code and releases live in the pnedev/comparePlus repository on GitHub.
How do you change the highlight colors?
Open Plugins > ComparePlus > Settings and use the color chooser there. The release notes list it, and v3.0.0 optimized it.
Merging Differences After a File Comparison
A comparison in Notepad++ can end in a merge. ComparePlus equalizes a difference when you click its margin symbol, and it applies patches built from a comparison.
Start with the smallest scope, so a wrong move costs you one block and not the whole file. Click the margin symbol to equalize a single difference. Filter the view, then copy or delete only the visible lines. When you need more, generate a unified diff patch and apply it to the old file.
Patches have one documented limit. Revert patch can fail when the patch came from a comparison with ignore options enabled, because the context lines no longer match (ComparePlus release notes, v2.0.0).
So turn the ignore options off before generating any patch you plan to reverse.
- Claude Code PyCharm Setup: Using the Agent Inside JetBrains - November 15, 2026
- Notepad++ for Mac: Does It Exist and What to Use Instead - November 13, 2026
- What Communications Teams Should Ask Before Commissioning a Mobile App - November 12, 2026
