How to make a PDF small enough to email

Updated October 11, 2026

Gmail stops attachments at 25 MB, and plenty of company mail systems stop earlier. When your PDF is rejected, the first instinct is to run it through a compressor. That sometimes works and sometimes does nothing, and it helps to know why.

Why a PDF gets big

Text is cheap. A page of plain text takes a few kilobytes. Pictures are expensive. A scanned document is a stack of photographs of pages, and a presentation exported with full-size photos carries every pixel. When a PDF is huge, the images are almost always the reason.

Try lossless compression first

Compress PDF repacks the file's internal data without touching image quality. The pages look exactly the same afterwards, because nothing is downsampled. It runs in your browser, so the file is not uploaded.

  1. Open Compress PDF and add your file.
  2. Click Compress.
  3. Compare the new size with the original, then download.

How much you save depends on how the file was made. A PDF exported from a program that left its data loosely packed can shrink a lot. A file that is already tightly packed barely moves, and the tool tells you it could not make it smaller.

If it barely shrinks

Nothing went wrong. The weight is in the images, and the main way to shrink images is to lower their resolution. This tool never does that, by design, so it can never blur a scan. You have other options:

  • Drop pages you do not need with Remove Pages, which is free. A long appendix or a run of duplicate pages can be a large share of the file.
  • Split the file in two with Split PDF and send two emails.
  • Go back to the source. If the PDF came from Word, Pages or a design program, export it again with smaller images. If it came from a scanner, rescan at a lower resolution, such as 150 dpi for plain documents.

Sending it another way

A shared link from a cloud drive avoids the size limit, but it means uploading the file to a cloud service, which may be exactly what you were trying to avoid. For a sensitive document, two smaller emails are often the better trade. If you are weighing that choice, this guide on uploading PDFs lays out the reasoning.

Free and Pro

Compress PDF is free, with three runs a day and a small PDFLocal link on the output. Pro removes both for a one-time $19.