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Compare files · Windows

How to Compare Two Files in Windows

Windows has no diff command by that name, but it has two comparison tools out of the box and several excellent free ones. Here is which to use when.

fc: the classic command

fc (file compare) is in every Windows version. /N prints line numbers, /W ignores whitespace differences, /C ignores case and /B compares byte by byte for binary files. It prints the mismatching blocks from each file with a few lines of context.

C:\> fc /N app.conf app.conf.new
Comparing files app.conf and APP.CONF.NEW
***** app.conf
    3:  workers = 4
***** APP.CONF.NEW
    3:  workers = 8
*****

PowerShell: Compare-Object

Compare-Object works on any two collections, including the lines of two files. The SideIndicator column shows which file a line came from: => the second, <= the first. Add -IncludeEqual to see matches too, or -SyncWindow to control how far it searches for a match.

PS> Compare-Object (Get-Content app.conf) (Get-Content app.conf.new)

InputObject  SideIndicator
-----------  -------------
workers = 8  =>
timeout = 30 =>
workers = 4  <=

WinMerge for a visual diff

WinMerge is a free, open-source diff tool with side-by-side highlighting, folder comparison, three-way merges and a Windows Explorer context menu. It is the usual answer when you want to see and merge changes rather than read a report.

Editors you may already have

VS Code compares two files without an extension (select both, right-click, Compare Selected). Notepad++ needs the ComparePlus plugin. Both are covered in their own guides. For two pieces of text that are not files yet, paste them into the online diff checker.

Compare two texts online Paste both versions. Runs in your browser, nothing is uploaded.

FAQ

Does Windows have a diff command?

Not by that name. fc is the built-in equivalent for text and binary files, and Compare-Object is the PowerShell way. If you have Git for Windows, git diff --no-index works too.

How do I compare two files in Notepad?

Notepad cannot compare files. Use fc from a command prompt, VS Code, or Notepad++ with the ComparePlus plugin.

How do I compare two folders in Windows?

WinMerge opens two folders and lists differing files; robocopy source dest /L /E lists what would be copied without copying anything, which doubles as a quick comparison.