Compress PDF Online for Free
Reduce the file size of a PDF by recompressing its embedded photos. Processed in your browser, with an honest before-and-after size comparison.
How to Compress a PDF Online for Free
- 1
Choose your PDF
Select or drag in the PDF you want to shrink. It opens directly in your browser.
- 2
Pick a compression level
Choose Balanced for minimal quality loss, or Smaller file size for maximum reduction.
- 3
Review and download
See the exact size reduction, then download the compressed file.
What This Tool Actually Does
Most of a PDF's file size usually comes from its embedded images, not its text. This tool finds embedded JPEG photos using a standard RGB color space and recompresses them at a lower quality — the same photo, with more aggressive JPEG compression. Text, fonts, and vector drawings are never touched, so documents stay fully searchable and selectable. Grayscale and CMYK images, and non-JPEG image formats, aren't recompressed in this version.
When a PDF Won't Get Smaller
A PDF made mostly of text and vector graphics — most contracts, forms, and documents exported from word processors — has little or nothing for this tool to compress, since there usually aren't large embedded photos to begin with. In that case, the tool says so directly instead of claiming a reduction that didn't happen, and still lets you download the original file.
Compressing Without Uploading Your Document
Compression happens entirely in your browser using pdf-lib and the browser's own image encoder — there is no document-upload step. See sign a PDF without uploading for the same explanation in more detail, and how to verify it yourself.
Frequently Asked Questions About Compressing PDFs
Yes. Compressing a PDF is free and doesn't require an account.
It recompresses embedded photos (JPEG images with a standard RGB color space) at a lower quality. Text, fonts, and vector graphics are left completely untouched — nothing is rasterized, so selectable text stays selectable.
No, and we won't tell you it did if it didn't. A PDF that's mostly text or vector graphics, or that has no recompressible images, may see little or no size reduction — the tool tells you honestly when that happens and still lets you download the original file.
No. Compression happens locally in your browser — your file's contents are never sent anywhere.
Recompressed images use a lower JPEG quality setting, which can introduce visible compression artifacts, especially at the "Smaller file size" level. Choose "Balanced" if image quality matters more than file size.