Compress a PDF
Most of the weight in a large PDF is embedded images. This finds them, recompresses them at a quality and resolution you choose, and rebuilds the document. Text and vector graphics are left alone, so the words stay sharp however hard you push.
How to compress a PDF
- 1Pick a presetMinimal Loss keeps images at full resolution and 90% quality. Balanced halves nothing and drops quality to 65%. Maximum Compression scales images to half resolution at 40% quality.
- 2Adjust if you need toThe advanced controls expose image quality, resolution scale, the size threshold below which images are skipped, and whether to strip document metadata.
- 3Compress and compareThe result shows the original and final size side by side, with a preview of the first page so you can judge the quality before downloading.
Questions
Are my files uploaded to a server?
No. The file is read by your browser and processed in the page. It never reaches a server, so there is no upload to wait for, no queue, and no copy of your document sitting somewhere with a retention policy.
Why did my PDF barely get smaller?
Because it was probably already mostly text. Compression works on embedded raster images; a document of vector text and line art has little to squeeze. Scanned documents, which are images of pages, tend to shrink the most.
Will the text get blurry?
No. Text and vector graphics are copied through untouched at every setting. Only raster images are recompressed, so the worst case is softer photographs, not fuzzy type.
Why does it take a while on big files?
Every embedded image is decoded and re-encoded. That work runs in a Web Worker so the page stays responsive, but a document with hundreds of photographs still takes real time.