Dupe guide

Find duplicate MP3 files on Mac

MP3 collections from years of downloads, rips, and library merges end up duplicated. Here's how to find them by audio bytes, not tags.

4 min read

If your MP3 collection has been around long enough to predate streaming, it’s almost certainly duplicated. Same album ripped to two different folders. The same song downloaded from two blogs in 2008. Library exports from a friend’s iPod. Eight folders deep, you have no idea what’s a copy and what isn’t.

Two paths

The native way: Music.app + Finder sort

If your MP3s are in Music.app’s library, use the built-in duplicate finder:

  1. Open Music.
  2. File > Library > Show Duplicate Items (Option-click for Exact Duplicates).
  3. Sort by Name or Album, review pairs, right-click extras and “Delete from Library.”

For loose MP3s in Finder, sort by Size in List view — adjacent files with identical sizes are duplicate candidates. Use shasum file1.mp3 file2.mp3 in Terminal to confirm.

The Music.app approach misses loose MP3s. The Finder approach misses anything renamed or organized into different folders. And both approaches struggle when ID3 tags are inconsistent — the same song tagged with different album art or different artist conventions looks like two different tracks to Music.app, even when the audio is identical.

The Dupe way

Dupe hashes the raw bytes of each MP3 with SHA-256. Tags don’t factor in.

  1. Install Dupe and open it.
  2. Click “Add Folder” and add every folder where MP3s might live — Music, Desktop, Downloads, old iTunes Music folders from migrated libraries.
  3. Click “Scan.”
  4. Browse duplicate groups. Each group shows file paths and sizes so you can pick which copy to keep.
  5. Select copies to remove and click “Move to Trash.”

An important nuance: two MP3s of the same song encoded at different bitrates (say, 192 kbps and 320 kbps) are not byte-identical, so Dupe won’t lump them together. That’s the right call — you probably want to keep the higher-bitrate version and toss the lower one, but that’s a manual decision Dupe deliberately leaves to you.

Safety guarantees:

For old MP3 collections built up over years, a single scan typically finds tens of gigabytes of exact duplicates.

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