Dupe guide

Find duplicate PDFs on Mac

PDFs pile up in Downloads, Documents, and email attachments. Here's how to find exact duplicate PDFs without trusting filenames.

4 min read

PDFs are the file format most likely to live in eight different folders. You download a receipt, email yourself a copy, save it to a “Taxes 2024” folder, and the next year you do the same thing again. Multiply that across years of bank statements, e-tickets, manuals, and academic papers, and your Downloads folder is half PDFs that exist elsewhere.

Two paths

The native way: Finder + Preview

You can find some PDF duplicates manually:

  1. Open Finder and use Cmd+F to search “Kind: PDF” across your home folder.
  2. Switch to List view and sort by Size.
  3. Look for adjacent files with identical sizes — duplicate candidates.
  4. Open suspected pairs in Preview to verify they’re the same document.
  5. Drag duplicates to the Trash.

This works for a handful of files. The problem is that PDFs are often saved with different filenames — bank_statement.pdf, Statement_03_2024.pdf, Untitled.pdf, bank_statement (1).pdf — and Finder can’t see that the contents are identical without you opening every pair.

The Dupe way

Dupe SHA-256-hashes the PDF bytes themselves. Two PDFs are duplicates if and only if their contents are byte-for-byte identical, no matter what they’re called.

  1. Install Dupe and open it.
  2. Click “Add Folder” and add Documents, Downloads, Desktop, and any iCloud Drive folders where PDFs accumulate.
  3. Click “Scan.”
  4. Filter or sort the duplicate groups by file extension to focus on PDFs.
  5. Review groups — Dupe shows full paths so you can see whether a copy is in Downloads versus a tagged archive folder.
  6. Move the redundant copies to the Trash.

A subtle point about PDFs: two PDFs that “look the same” but were produced by different export passes (say, “Save as PDF” from two different apps, or one with embedded fonts and one without) will have different bytes, and Dupe will keep them both. That’s deliberate — they aren’t actually the same file, even if they render identically. If you want one of them gone, you have to decide which.

Safety:

One scan typically removes hundreds of duplicate receipts, statements, and saved web pages from a long-lived Downloads folder.

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