A single misplaced character in a config file can break a deployment. Knowing exactly what changed between two versions of a file is not optional.
Learning how to compare two files in Notepad++ takes less than 5 minutes once you know the right plugin and the correct steps.
This guide covers everything: installing the Compare plugin, running a side-by-side diff, reading the color-coded output, handling encoding mismatches, and fixing the most common errors.
It also covers when to skip Notepad++ entirely and use a dedicated diff tool instead.
What Is the Compare Plugin in Notepad++?
The Compare plugin is a free Notepad++ extension that highlights line-by-line differences between 2 open files, displayed side by side in a split view. It uses color-coded markers to show added, removed, changed, and moved lines, with synchronized scrolling between both panels.
Notepad++ does not include a built-in diff tool. The Compare plugin fills that gap without requiring any external software.
It is separate from the native “Move/Clone to Other View” feature in Notepad++, which opens two files side by side but does not highlight any differences. The Compare plugin is what actually runs the diff.
According to the 2025 Stack Overflow Developer Survey (49,000+ respondents), Notepad++ holds 27.4% usage share among developers worldwide. File comparison is one of the most common workflows that keep it relevant alongside heavier IDEs.
What does the Compare plugin actually do?
The plugin runs a diff algorithm against 2 open Notepad++ tabs and renders the output directly inside the editor.
- Displays differences in a synchronized side-by-side split layout
- Color-codes every added, deleted, moved, and changed line
- Shows a compact navigation bar for jumping between diff markers without manual scrolling
- Supports diff against Git and SVN history through the libgit2.dll and sqlite.dll libraries bundled in the plugin subfolder
- Does not modify either file; it only renders a visual overlay
ComparePlus (the successor project on GitHub by developer pnedev) extends this further with character-level diff highlighting and support for ARM64 architecture. Compare plugin v2.0.0 remains the stable, widely used version as of 2025.
Who uses it and for what
Typical use cases:
Developers: comparing two versions of a config file, reviewing script changes, or checking code edits before a commit.
Sysadmins: spotting differences in log files, deployment configs, or exported settings across environments.
QA testers: comparing test output files or verifying that a build produced the expected results against a baseline.
Landbase data from 2025 tracked 411 verified companies still actively using Notepad++, with the education sector leading adoption and the US, UK, and Canada as the top 3 geographies.
How to Install the Compare Plugin in Notepad++
The Compare plugin installs in 2 ways: automatically through Plugins Admin (the faster route), or manually by placing the DLL into the correct plugins folder. The manual method is needed for offline environments or when Plugins Admin fails.
Before installing, press F1 inside Notepad++ to confirm whether your installation is 32-bit or 64-bit. The DLL versions are not interchangeable. Using the wrong architecture causes the plugin to fail silently.
Installing via Plugins Admin
Plugins Admin is available in Notepad++ v8.4.5 and above. This is the fastest install path.
- Open Notepad++ and go to Plugins > Plugins Admin
- In the Available tab, search for Compare
- Check the checkbox next to Compare (not just click the name)
- Click Install
- Notepad++ will close, install the plugin, and reopen automatically
After restart, go to Plugins in the menu bar. A “Compare” submenu confirms the plugin loaded correctly.
Manual DLL installation
Use this when Plugins Admin is unavailable, throws an error, or when you need the latest plugin version (the admin repository sometimes lags behind GitHub releases).
Step 1: Download the correct archive from the official GitHub release at github.com/pnedev/comparePlus/releases.
Step 2: Choose the right file based on your Notepad++ build.
| Architecture | File to download | Default install path |
|---|---|---|
| 64-bit | ComparePluginv2.0.0X64.zip | %ProgramFiles%\Notepad++\plugins |
| 32-bit | ComparePluginv2.0.0×86.zip | %ProgramFiles(x86)%\Notepad++\plugins |
| ARM64 | ComparePlus ARM64 release | %ProgramFiles%\Notepad++\plugins |
Step 3: Create a folder named ComparePlugin inside the plugins directory.
Step 4: Extract the ZIP contents into that new folder. The structure must be: pluginsComparePluginComparePlugin.dll plus the ComparePlugin subfolder containing libgit2.dll and sqlite.dll.
Step 5: Right-click the DLL file, go to Properties, and click Unblock if that option appears. Windows blocks DLLs downloaded from the internet by default, which prevents Notepad++ from loading the plugin.
Step 6: Restart Notepad++. The Compare submenu appears under Plugins if the install path and architecture were correct.
How to Compare Two Files Using the Compare Plugin
Open both files as separate tabs in Notepad++, then trigger the comparison through the Plugins menu or with the keyboard shortcut Alt+D. The plugin opens a side-by-side diff view with synchronized scrolling and color-coded difference markers.
The tab order matters. The first active tab before you run the comparison is treated as the “old” file (displayed on the left). The second tab is treated as the “new” file (right side).
Setting up the two files before comparing
Get the file order right before running the diff. Wrong tab order means the plugin treats additions as deletions and vice versa.
Option A (default order): Click the tab you want as the “old” reference, then open or switch to the second file. Run Compare. Notepad++ uses the sequence in which the tabs were last focused.
Option B (explicit control): Open both files, click the tab you want as the first reference, go to Plugins > Compare > Set as First to Compare, then click the second tab and run Compare. This is the reliable method when you have several tabs open.
Both files must be open as tabs in the same Notepad++ window. The plugin does not accept file paths as input.
Running the comparison
With both tabs open and the correct file set as first:
- Go to Plugins > Compare > Compare, or press Alt+D
- The split view opens immediately with differences highlighted
- Scrolling in either panel moves both panels at the same time
- Use Alt+N (Next Difference) and Alt+B (Previous Difference) to jump between diff markers
- To close the comparison view, go to Plugins > Compare > Clear Results
The navigation bar in the upper right corner maps every difference across the full file length. Clicking any colored segment in the bar jumps directly to that diff. This matters for large files where manually scrolling through hundreds of lines is slow.
How to Read the Color-Coded Diff Output
The Compare plugin uses 4 colors and matching gutter symbols to classify every line difference. Reading the output correctly is faster than re-scanning both files manually.
According to Retool’s 2022 State of Engineering Time survey, 34% of developers report merge conflicts as a recurring productivity blocker. A clear visual diff output directly reduces the time spent resolving those conflicts.
What each color and symbol means
| Color | Symbol | Meaning |
|---|---|---|
| Green | + | Line added in the new file (right side), not present in the old file |
| Red | – | Line removed from the old file, not present in the new file |
| Orange/yellow | Changed symbol | Line exists in both files but with modifications; the specific changed characters are highlighted inline |
| Gray/teal | Arrow | Line moved to a different position in the other file (content unchanged) |
Moved lines only appear when Detect Moves is enabled in the Compare plugin settings. It is on by default.
Navigating between differences
Keyboard shortcuts are faster than the menu:
- Alt+N: jump to the next difference in the file
- Alt+B: jump to the previous difference
- Alt+F: jump to the first difference
- Alt+L: jump to the last difference
The navigation bar (top-right corner of the Notepad++ window during comparison) shows a minimap of all diffs. Colored segments match the same color scheme as the highlighted lines. Clicking a segment scrolls both panels to that location.
For files above a few hundred lines, use the navigation bar. Scrolling manually through a large file comparison is how small differences get missed.
How to Compare a File Against Its Last Saved Version
Notepad++ with the Compare plugin supports comparing an open, unsaved file against the version currently written to disk. This requires no second file. Use Plugins > Compare > Compare to Last Save.
This only works when the file has been modified but not yet saved. Once you save the file (Ctrl+S), the disk version updates and the comparison baseline resets to the new saved state.
When to use Compare to Last Save
Best for: reviewing all edits made in the current session before writing them to disk. Useful before committing config changes to a production server, or before overwriting a script that was working correctly.
Not a substitute for version history: this feature compares against the last disk save only. It does not compare against Git commits, previous file backups, or any earlier version from before the current session. For that, use git diff or a dedicated version control workflow.
Practical example: You open a .htaccess file, make 12 edits across 40 minutes, and want to see every change at once before saving. Compare to Last Save shows the full diff in one view without requiring a second file or a manual copy.
How to Compare Two Files Using Built-In Split View (No Plugin)
Notepad++ includes a native split view that displays 2 files side by side without requiring any plugin. Right-click any tab and select Move to Other View, or use View > Move/Clone to Other View.
Split view shows both files simultaneously. It does not run a diff, highlight differences, or synchronize scrolling between the two panels.
Split view vs. Compare plugin
Use split view when:
- Files are short (under 50 lines) and differences are visually obvious
- You need to reference one file while editing the other
- The Compare plugin is not installed and installing it is not an option
Use the Compare plugin when:
- Files are longer than a few dozen lines
- You need to catch every difference, not just obvious ones
- You need to navigate diffs systematically rather than by eye
Split view is also the foundation the Compare plugin builds on. When you run a comparison, the plugin activates the split view automatically and then layers the diff highlighting on top of it.
One thing worth knowing: cloning a tab (Move/Clone > Clone) keeps the same file in both panels. That is useful for comparing two sections of a single long file side by side. It is not the same as comparing two distinct files.
How to Compare Two Files with Different Encodings
Encoding mismatches are the most common reason the Compare plugin shows every single line as different when the files appear identical. A UTF-8 file and an ANSI file with the same content will produce a full-file diff because the byte representations differ.
Check the encoding of both files before running the comparison. The current encoding is visible in the status bar at the bottom of the Notepad++ window.
Matching encodings before comparing
Go to Encoding in the menu bar. The checkmark shows the current file encoding. To convert a file, select Encoding > Convert to UTF-8 (or whichever target encoding matches the other file).
UTF-8 without BOM is the safest baseline for comparison. BOM (Byte Order Mark) characters at the start of a file trigger a false diff on line 1. Two files that differ only in BOM presence will show that first line as “changed” even though the visible content is identical.
The Compare plugin includes a Warn about encodings mismatch setting under Plugins > Compare > Settings. Enabling this shows a warning dialog when you run a comparison on files with different encodings, before the diff renders. Worth switching on permanently.
Line endings as a second mismatch source
CRLF (Windows) and LF (Unix/Linux) line endings are the second most common cause of false diffs. A file edited on Linux and opened on Windows often shows every single line as “changed” when the only difference is the line ending character.
Check line endings: View > Show Symbol > Show End of Line. CRLF appears as CR LF at the end of each line; LF files show only LF.
Convert line endings: Edit > EOL Conversion > Windows Format (CRLF) or Unix Format (LF). Match both files to the same format before comparing.
Getting encoding and line endings to match before running the diff eliminates the two most common sources of noise in Notepad++ file comparisons. A clean comparison then shows only real content differences.
How to Compare Two Files with Ignore Options Enabled
The Compare plugin includes 3 ignore filters that reduce noise in the diff output. Access them under Plugins > Compare > Settings, or toggle Ignore Spaces directly from the Compare submenu.
Each option targets a specific class of false differences. Using the wrong one hides real changes. Using none of them on noisy files makes the output hard to read.
What each ignore option does
Ignore Spaces: skips differences caused by whitespace character count or type. Useful for code files where indentation style changed but logic did not.
Ignore Case: treats uppercase and lowercase as identical. Available in ComparePlus (the successor plugin). The original Compare plugin v2.0.0 does not include this option natively, which is one reason the community moved toward ComparePlus.
Ignore Empty Lines: skips blank line additions or removals. Useful when comparing log files or config exports where blank lines vary but content is the same.
When to use each option in practice
Code review after reformatting: a linter or formatter like Prettier ran on one version but not the other. Enable Ignore Spaces. The structural diff disappears and only logic changes remain.
Config file comparison across systems: one file was edited on Linux (lowercase keys), one on Windows (mixed case). Enable Ignore Case in ComparePlus.
Log file comparison: two exported logs have different amounts of blank lines between entries. Enable Ignore Empty Lines to focus on actual content differences.
WinMerge uses the same 3-category ignore model (whitespace, case, blank lines) as its baseline filter set, which confirms these are the standard noise reduction categories across diff tools.
How to Compare Two Files via the Command Line in Notepad++
Notepad++ has no native CLI flag that triggers the Compare plugin automatically on launch. The Compare plugin stopped distributing compare.exe after v1.5.6.6, according to Notepad++ community records. Direct command-line comparison requires a different approach.
Using ComparePlus with a pluginMessage argument
ComparePlus (v1.0.0 and above) supports a -pluginMessage argument that can trigger a comparison when Notepad++ is not already running with an existing session.
The syntax is:
“ notepad++.exe -pluginMessage=compare file1.txt file2.txt `
Limitation: this only works reliably when Notepad++ is closed before the command runs. If Notepad++ is already open with a session containing other tabs, the file order may not map correctly to the comparison. The Notepad++ community flagged this as a known behavior in the ComparePlus GitHub issue tracker.
Using Windows FC command as a CLI alternative
FC (File Compare) is a built-in Windows command-line utility that runs text or binary diffs without opening any editor. It is the fastest option for scripted or automated file comparison workflows.
Basic syntax: fc file1.txt file2.txt
Useful switches:
- /c
- ignore case differences
- /w
- compress whitespace during comparison
- /b
- binary comparison mode
- /l
- compare as ASCII text (default for .txt files)
FC outputs mismatched lines directly to the terminal. No plugin, no GUI, no install required. For sysadmins comparing config files in deployment scripts, FC is the practical answer when Notepad++ is not part of the workflow.
If you use Git for version control, git diff is more powerful than FC for tracked files. It shows commit-level changes with context lines and supports word-level diffing with the –word-diff flag.
What Are the Limitations of the Compare Plugin in Notepad++?
The Compare plugin handles plain text and code files well. It does not handle 4 categories of comparison that developers regularly need: 3-way merges, binary files, very large files, and word-level inline diffs.
Knowing the limits before you hit them saves time. The plugin’s GitHub repository (pnedev/comparePlus) documents several of these constraints in open issues.
File type and size limits
Binary files: not supported. The plugin only diffs plain text, source code, and markup. Comparing .exe, .docx, .pdf, or image files requires a dedicated tool like Beyond Compare.
Large files: files above roughly 100MB cause significant slowdown or crash during diff rendering. The Scintilla editor component that Notepad++ runs on was not designed for very large file handling at diff speed.
No word-level inline diff in Compare v2.0.0: the plugin highlights changed lines but not the specific changed characters within a line. ComparePlus adds character-level diff detection. VS Code’s built-in diff viewer also shows inline word-level changes by default.
Merge and multi-file limits
3-way merge is not supported. There is no common ancestor comparison mode. If you need to resolve a conflict between 3 versions of a file (a common need in Git workflows), you need KDiff3, WinMerge, or Beyond Compare.
The standard Compare plugin compares exactly 2 files per session. ComparePlus supports multiple active compared file pairs simultaneously, which is its main structural improvement over the original plugin.
There is also no built-in export of diff results. The comparison output exists only as a visual overlay inside Notepad++. Generating a patch file, an HTML diff report, or a unified diff output requires a separate tool such as git diff or a dedicated diff utility.
How to Fix Common Compare Plugin Errors in Notepad++
Most Compare plugin failures fall into 5 categories: wrong DLL architecture, version incompatibility, encoding or line ending mismatch, file size, and an insufficient number of open tabs. Each has a specific fix.
| Error | Cause | Fix |
|---|---|---|
| Plugin not in menu after install | Wrong DLL architecture (32/64-bit mismatch) | Press F1 to confirm build, reinstall matching DLL |
| Compare option grayed out | Only 1 tab open | Open a second file in a separate tab |
| All lines flagged as different | Encoding or CRLF/LF mismatch | Match encodings and line endings before comparing |
| Notepad++ crashes on compare | File too large for plugin rendering | Use WinMerge or git diff for large files |
| Installation error from Plugins Admin | Firewall blocking GitHub, or insufficient permissions | Run Notepad++ as admin, or install manually from GitHub |
Architecture mismatch fix in detail
This is the most common cause of the plugin not appearing in the menu. A 32-bit DLL placed in a 64-bit Notepad++ plugins folder loads silently and fails.
Press F1 in Notepad++ to open the About dialog. The build architecture (x86 or x64) appears in the version string. Download the matching DLL from github.com/pnedev/comparePlus/releases.
After placing the correct DLL, right-click it, open Properties, and click Unblock if the option is present. Windows blocks DLLs sourced from the internet by default. Missing this step causes the plugin to fail even when the architecture is correct.
Installation failure via Plugins Admin
Two common causes: Notepad++ not running as administrator, and firewall rules blocking GitHub (some corporate firewalls classify github.com as “software downloads/hacking”).
Right-click the Notepad++ shortcut and select Run as administrator, then retry Plugins Admin. If the firewall is the issue, download the ZIP manually from GitHub on a machine with access and copy it to the target machine for manual installation.
Enabling TLS 1.2 under Control Panel > Internet Options > Advanced > Security also resolves installation failures on older Windows configurations where TLS 1.0/1.1 is the active default.
What Are the Alternatives to the Compare Plugin for File Diffing?
4 tools cover the comparison needs that Notepad++ cannot handle: WinMerge for folder-level diffing, Beyond Compare for binary and multi-format comparison, VS Code for Git-integrated word-level diff, and KDiff3 for 3-way merge.
The text editor market that includes these tools was valued at $2.5 billion in 2024 and is projected to grow at a CAGR of 5.9% through 2035, according to Verified Market Reports. File comparison tooling is a consistent part of that ecosystem.
WinMerge
Free, open source, Windows only. Actively developed since 2000 with v2.16.56 as the current stable release.
- Compares files and entire folder trees
- 3-way file and folder comparison
- Shell integration (right-click from Windows Explorer)
- Archive comparison via 7-Zip integration
Best for: developers who need folder-level diff or 3-way merge without paying for a tool. WinMerge is the most direct free upgrade from the Notepad++ Compare plugin when you hit its limits.
Beyond Compare
Paid tool ($30 standard, $60 pro per license). Available for Windows, macOS, and Linux. Scooter Software has maintained it since 1996.
Handles text, binary, images, tables, registry hives, FTP sites, and structured data formats. The 3-way merge mode and folder synchronization features make it the standard choice for teams with complex versioning workflows.
Key differentiator: context-aware comparison rules. You can define what “changed” means per file type, filtering out irrelevant differences automatically.
VS Code built-in diff viewer
Free, cross-platform, Git-integrated. The diff viewer in VS Code shows word-level inline changes by default, which the Notepad++ Compare plugin does not.
To compare 2 files in VS Code: right-click a file in the Explorer panel, select Select for Compare, right-click the second file, then select Compare with Selected.
For version-controlled files, the built-in source control panel shows a diff view against the last commit directly from the editor sidebar. No plugin required.
KDiff3
Free, open source, cross-platform (Windows, macOS, Linux). The main use case is 3-way merge for resolving conflicts between a base version, a local branch, and a remote branch.
KDiff3 integrates with Git as a merge tool via git config –global merge.tool kdiff3. Development activity has slowed in recent years, but the tool remains stable and widely referenced in Git configuration guides.
| Tool | Cost | 3-way merge | Best for |
|---|---|---|---|
| WinMerge | Free | Yes | Folder comparison, Windows workflows |
| Beyond Compare | $30–$60 | Yes | Binary, multi-format, team use |
| Visual Studio Code diff | Free | No | Git-integrated, word-level diff |
| KDiff3 | Free | Yes | Git merge conflict resolution |
FAQ on How To Compare Two Files In Notepad++
Does Notepad++ have a built-in file comparison tool?
No. Notepad++ does not include a native diff tool. You need to install the Compare plugin through Plugins Admin. It adds side-by-side comparison with color-coded difference highlighting directly inside the editor.
How do I install the Compare plugin in Notepad++?
Go to Plugins > Plugins Admin, search for “Compare,” check the checkbox, and click Install. Notepad++ restarts automatically. For offline installs, download the correct 32-bit or 64-bit DLL from the plugin’s GitHub releases page.
What keyboard shortcut runs the file comparison?
Press Alt+D with both files open as tabs. This triggers the comparison immediately without opening any menu. Use Alt+N and Alt+B to jump between the next and previous differences in the diff output.
Why does the Compare plugin show every line as different?
The most common cause is an encoding mismatch. A UTF-8 file compared against an ANSI file produces a full-file diff. Match encodings via the Encoding menu before comparing. CRLF vs LF line ending differences cause the same problem.
Can I compare a file against its previously saved version?
Yes. Go to Plugins > Compare > Compare to Last Save. This works only when the file has unsaved edits. It shows every change made since the last disk save, with no second file required.
Why is the Compare option grayed out in the menu?
The plugin requires exactly two open tabs. If only one file is open, the Compare option is unavailable. Open a second file in a separate tab, then run the comparison again from the Plugins menu.
Can I compare files without the Compare plugin?
Yes, using Notepad++’s native split view. Right-click any tab and select Move to Other View. Both files display side by side, but differences are not highlighted. This works for short files where changes are visually obvious.
Does the Compare plugin work with Notepad++ 64-bit?
Yes, but you must install the 64-bit DLL version. A 32-bit DLL placed in a 64-bit Notepad++ plugins folder fails silently. Press F1 in Notepad++ to confirm your build architecture before downloading the plugin.
What do the colors mean in the comparison output?
Green marks added lines, red marks deleted lines, orange marks changed lines, and gray marks lines moved to a different position. The same color scheme appears in the navigation bar for quick scanning across large files.
What should I use instead of Notepad++ for complex file comparison?
WinMerge handles folder comparison and 3-way merge for free. Beyond Compare supports binary and multi-format diffing. VS Code’s built-in diff viewer shows word-level inline changes. Use these when the Compare plugin hits its limits.
Conclusion
This conclusion is for an article presenting how to compare two files in Notepad++ using the Compare plugin, color-coded diff output, and ignore options that cut through encoding noise.
The plugin handles most day-to-day text comparison and code review tasks well. Install it once and it stays useful for config files, log analysis, and script versioning.
When you hit its limits, WinMerge covers folder-level diffing for free. Beyond Compare handles binary files. Git diff is the right call for version-controlled codebases.
Pick the right tool for the file type and the job. Notepad++ gets you most of the way there.
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