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How to reduce PDF file size

A PDF that's too large can bounce back from email or stall on upload. Reducing its file size makes it easy to share, while keeping the document readable.

This guide explains what makes PDFs large, how compression works, and how to shrink a PDF for free in your browser.

Open the Compress PDF tool

Why PDFs get large

Most oversized PDFs are heavy because of images — scanned pages, photos and screenshots store a lot of data. Text, by contrast, is tiny. That's why scanned documents compress far more than text-only files.

Compress a PDF in your browser

The fastest free method runs entirely on your device and lets you choose the quality.

  1. 1Open the Compress PDF tool.
  2. 2Drag in your PDF or click to select it.
  3. 3Choose a quality level — Recommended balances size and clarity.
  4. 4Download the smaller file and check the before/after size.

Get the smallest size without ruining quality

Start with the Recommended setting and only move to a stronger level if you still need a smaller file.

If your PDF is mostly text, it's already small — expect modest savings.

For emailing, aim to stay under your provider's attachment limit (often 20–25 MB).

Frequently asked questions

Ready to try it?

Reduce PDF file size while keeping readable quality.

Use Compress PDF