Compress PDF files in your browser
Pick a quality level and compress PDF files to a smaller size for email and upload forms, without sending them to a server.
Last updated
Your files never leave your device. Everything is processed in your browser and nothing is uploaded.
How to compress PDF files
- Press Choose PDF, or drop a PDF onto the box.
- Read the warning: compressed pages become images.
- Set the image quality. 60 is a good balance for scans.
- Press Compress PDF and wait while each page is processed.
- Compare the original and new size, then download the compressed file.
How the PDF compressor works
The compressor draws each page with pdf.js, the engine behind Firefox's PDF viewer, at about 108 pixels per inch, saves it as a JPEG at the quality you choose, and builds a new PDF from those images with pdf-lib. Each page keeps its original size, so the document prints the same.
This works best for scanned documents and image-heavy files, where the original pages are already pictures. Because every page becomes an image, text in the compressed file can't be selected, searched or copied, and links stop working. Always keep your original. Nothing is uploaded at any point.
Formula
Image size per page = page size in points × 1.5 pixels. An A4 page (595 × 842 points) becomes an image of about 892 × 1,263 pixels.
Saving = (original size − new size) ÷ original size × 100%.
Example
A 9-page scanned application of 8.4 MB, compressed at quality 60, often comes out somewhere around 1 to 2 MB. If it ends at 1.5 MB, the saving is (8.4 − 1.5) ÷ 8.4 × 100, about 82%.
A 20-page text report made in a word processor may be only 300 KB to begin with. Turning its pages into images can make it bigger, and the tool tells you when that happens so you can keep the original.
Tips and common mistakes
Compress scans, not text documents
Files exported from Word or Google Docs are usually small already. Compression helps most with scans and photos.
Lower quality for email, higher for print
Quality 40 to 60 keeps scans readable on screen; use 70 or more if the document will be printed.
Only send the pages that matter
Fewer pages means a smaller file. Split out the pages you need before compressing.
Building a PDF from photos?
Compress each photo first, then turn the images into a PDF and keep text-free pages small.
Frequently asked questions
Will I still be able to select text?
No. Compressed pages become images, so text can't be selected, searched or copied. Keep the original if you need that.
Is my PDF uploaded?
No. Pages are processed in your browser and the file never leaves your device.
Why did my file get bigger?
PDFs made mostly of text are already compact. Turning their pages into pictures can add size, so keep the original in that case.
Can I compress a password-protected PDF?
No. Remove the password in your PDF reader and save an unprotected copy first.