Compress PDF
Reduce the file size of a PDF with lossless optimisation, smaller images or full-page compression for scans — and see exactly how much each method saves. Your file never leaves your device.
Runs in your browser — nothing is uploaded Free, no limits
How to use the Compress PDF
- Choose or drop the PDF you want to shrink.
- Pick Auto to try every method, or choose Lossless, Balanced or Strong yourself.
- For Balanced and Strong, set the resolution and JPEG quality (lower = smaller).
- Click Compress PDF, compare the before and after sizes, and download the result.
Frequently asked questions
How much smaller will my PDF get?
It depends on what's inside. Scanned pages and photos can often shrink by 50–90% with Balanced or Strong. Text-only PDFs are usually already compact, so lossless optimisation may save only a few percent — and sometimes nothing.
What's the difference between the modes?
Lossless re-packs the file without changing any content. Balanced also re-encodes large photos as smaller JPEGs while keeping text and vector graphics sharp. Strong turns each page into an image — the biggest saving for scans, but the text is no longer selectable or searchable.
Why is my compressed file not smaller?
Some PDFs are already well optimized, or contain mostly text and vector graphics that can't be squeezed further without losing quality. When a result is bigger than your original, the tool tells you and doesn't offer it.
Is browser compression as good as desktop software?
For images and scans it is close. Professional desktop tools can also subset fonts, convert colour spaces and downsample images based on their exact size on the page, so they sometimes squeeze text-heavy files a little further.
Is my PDF uploaded to compress it?
No. Compression runs entirely in your browser, so confidential documents never leave your device. Large files simply take longer on slower computers.
Will Strong compression keep my links and form fields?
No. Strong mode rebuilds the PDF from page images, so links, bookmarks, form fields and selectable text are lost. Use Lossless or Balanced to keep them.