How to Compress a PDF Without Losing Quality

What makes a PDF big

• Scanned pages. Every page of a scan is a picture, often saved at 300–600 DPI.
• Photos. Pictures from phones and cameras are several megabytes each.
• Text and vector graphics are tiny by comparison. A 50-page report without images is often under 1 MB.

That's why compression works so well on scans and photo-heavy documents, and changes little in text documents.

Compress a PDF step by step

1. Open Compress PDF and add one or more PDFs.
2. Choose a level: Low, Recommended or Extreme.
3. Click Compress PDF. The result shows how much smaller the file got.
4. Download the compressed PDF. Several files download together as a ZIP.

Large images are resampled to the level's resolution and saved as high-quality JPEGs, then the rest of the file is recompressed without any loss. Text, fonts and vector drawings aren't touched, and a file is never made bigger. Everything happens in your browser, so nothing is uploaded.

Which level should you choose?

• Low keeps images at up to 220 DPI. Use it for documents you'll print.
• Recommended uses 150 DPI, the best balance for email, WhatsApp and upload portals.
• Extreme uses 96 DPI and stronger JPEG compression. It's fine for reading on screen, but small print in scans may look softer.

Need a specific size, like 300 KB?

Upload portals often state an exact limit. Choose Target file size in Compress PDF and pick or type the limit; the tool tries progressively stronger settings and keeps the sharpest version that fits. There are ready-made pages for common limits: 100 KB, 200 KB, 300 KB, 500 KB and 1 MB.

Still too big?

• Remove pages nobody needs with Remove Pages.
• Cut the file into parts under a size limit with Split by Size and send them separately.
• Rescan at 200–300 DPI instead of 600. It's still sharp and far smaller.

Compress last: merge, sign and edit first, then compress the final file once.

Common problems and fixes

The file barely got smaller.

It probably contains mostly text, which is already compact, or its images are already compressed. Try Extreme for scans; for text documents, removing pages is the only way to make it much smaller.

Images look blurry after compressing.

Use Low, which keeps images at up to 220 DPI, or Recommended if you used Extreme.

It says the PDF is password-protected.

Remove the password with Unlock PDF first, compress, then add it back with Protect PDF if you need to.

Colours in a photo look slightly different.

Recompressed images are saved as standard RGB JPEGs. CMYK images, used in print-ready files, are left exactly as they were; for press work, use Low or skip compression.

Frequently asked questions