PDF Compressor
Reduce PDF file size while keeping content intact.
How to Use PDF Compressor
- 1Click the upload area or drag and drop your PDF file into the drop zone.
- 2Click 'Compress PDF' to start the compression process in your browser.
- 3The tool will display the original and compressed file sizes along with the percentage saved.
- 4Click 'Download Compressed PDF' to save the smaller file to your device.
Frequently Asked Questions
How does the PDF compressor reduce file size?
The tool re-saves your PDF using object streams, which pack multiple PDF objects into single compressed streams. This is most effective on PDFs with lots of metadata, redundant cross-reference tables, or uncompressed object streams.
Why is my compressed PDF the same size or larger?
Some PDFs are already optimised — they use compressed streams internally. In that case the compressor will notify you and you can still download the re-saved file, but the size difference will be negligible.
Does this remove images or reduce their quality?
No. The tool only re-structures the PDF's internal layout. Images, fonts, and all content remain identical.
Is my PDF uploaded to a server?
No. Everything happens in your browser using JavaScript. Your file never leaves your device.
About PDF Compressor
PDF files can grow surprisingly large over time — especially when created by design software, scanned from a printer, or assembled from multiple sources. Our PDF Compressor provides a quick, browser-based way to reduce file size without losing any content.
The compression works by re-encoding the PDF's internal structure using object streams, a feature of the PDF 1.5 specification. This packs the cross-reference table and object metadata more efficiently, often reducing overhead in PDFs generated by older tools or applications that don't optimise their output.
Because all processing is done locally in your browser using the pdf-lib library, your documents stay completely private. There's no file upload, no cloud processing, and no data retention. The compressed PDF is generated on your device and downloaded directly to your downloads folder.
For maximum compression — especially for scanned documents with large images — a desktop tool like Ghostscript or Adobe Acrobat can re-encode embedded images at lower resolution. Our tool complements those by handling the structural overhead that browser-based JavaScript can address.