PDF Compressor

Lossless mode loads the file with pdf-lib, re-serializes the object graph into compressed streams, and strips redundant title, author, subject, keyword, creator, and producer metadata. Raster mode renders each page with PDF.js and re-encodes it as a JPEG at a chosen quality before pdf-lib reassembles the document.

Text and form-heavy PDFs, or files that have been edited and re-saved many times, typically shrink 10-35 percent with lossless compression because it removes unused objects and revision layers. Scanned or photo-heavy pages respond far better to the Smallest raster preset, often shrinking 50-80 percent, at the cost of selectable text.

Lossless mode preserves every pixel and reflows nothing, so the document looks identical. Raster mode rebuilds each page from an image, so sharp text can soften slightly on the Smallest preset and the pages become non-searchable; the Balanced preset is the recommended middle ground.

No. Compression runs entirely in your browser using pdf-lib and PDF.js, and the input file plus the output are both held in memory on your device. Nothing is transmitted, stored, or shared, so sensitive documents stay private.

An already-optimized PDF (one authored with a modern tool or compressed before) may have little to compress, and the Smallest raster preset renders at a lower resolution, so on very small files the overhead can offset the savings. In that case try Balanced or lossless instead.