WinMerge shows exactly what changed between two files or folders.

File Comparison

File → Open. Select left and right files. Differences are highlighted by color: yellow for changed lines, red for deleted, green for added. The location pane on the left shows a mini-map of all differences.

Click the arrow buttons in the diff gutter to merge individual changes from one side to the other. Copy to right copies the left version; copy to left does the reverse.

Folder Comparison

File → Open → select two folders. WinMerge lists all files color-coded: identical (white), different (yellow), only on left (red), only on right (green). Double-click any file to see the detailed diff. Right-click → “Copy to Right” or “Copy to Left” to sync individual files.

Filters

Tools → Filters. Create file masks to include or exclude certain patterns. Common filters: exclude node_modules/, *.min.js, .git/. Apply generation filters to ignore line-ending differences or whitespace changes.

Keyboard Shortcuts

  • Alt+↓ — Next difference
  • Alt+↑ — Previous difference
  • Alt+← — Copy left to right
  • Alt+→ — Copy right to left
  • F5 — Refresh comparison
  • Ctrl+W — Close