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Compress a PDF to reduce its file size

Compress a PDF to reduce its file size

Use Compress PDF on Mac or Compress on iPhone and iPad to make a PDF smaller, for example before emailing or uploading it. Compression works best on scanned documents and PDFs that contain photos.

Compress a PDF

  1. Open PDF Split & Merge.
  2. On Mac, select Compress PDF in the sidebar. On iPhone and iPad, select Compress.
  3. Click or tap Choose PDF..., or drag a PDF into the drop area. The current page count and file size are shown.
  4. Under Quality, choose High Quality, Balanced, or Smallest File.
  5. Click or tap Compress PDF....
  6. On Mac, choose where to save the compressed PDF. On iPhone and iPad, wait for processing to finish and then choose a destination in the Files export sheet.

When it finishes, the app shows the original and new file sizes. The original PDF is never changed.

Choosing a quality level

  • High Quality keeps images sharp and gives a moderate size reduction.
  • Balanced looks good on screen and usually makes the file much smaller. This is the default.
  • Smallest File gives the biggest reduction. Fine detail and small text in images may look soft.

What happens to text and links

The app compresses a PDF by converting image-heavy pages, such as scans and photos, into compressed images. A page is only converted when that makes it noticeably smaller.

  • Pages that are converted to images lose selectable and searchable text, links, and form fields.
  • Pages that would not get smaller, such as most text-only pages, are kept exactly as they are.
  • Bookmarks and document information are kept.
  • If the original PDF has security restrictions, such as not allowing copying, the compressed PDF keeps the same restrictions.

The result message tells you how many pages were converted to images.

Output file names

The suggested file name uses this format:

Original File Name (Compressed).pdf

If the PDF is already optimized

If compression would not make the file at least 10% smaller, the app shows Already Optimized and does not save a new file. This is common for PDFs that contain mostly text. Try Smallest File for a stronger reduction, or keep using the original.

If the PDF is password protected

PDFs that require a password to open cannot be compressed. Open the PDF in another app, remove the password, and then try again.