Compress PDF
Reduce PDF file size for email, web upload or storage. Three quality levels.
What is PDF compression?
PDF compression reduces the file size of PDF documents by optimizing images, removing unnecessary metadata, and streamlining the document structure. Large PDFs are common when documents contain high-resolution images, embedded fonts, or redundant data. Compression makes files easier to email, faster to upload, and cheaper to store.
This tool compresses PDFs in your browser — no server upload required. Your documents remain completely private. The compression focuses primarily on image optimization (which accounts for the majority of PDF file size) and removal of unnecessary metadata while preserving text quality and document structure.
How to use this tool
Upload a PDF and select a compression level (low, medium, or high). Low compression preserves the best quality with modest size reduction. High compression achieves the most size reduction but images may appear slightly softer. The tool shows the original and compressed file sizes with the percentage reduction.
Compression levels
- Low — minimal quality loss, 10-30% size reduction. Best for documents you will print.
- Medium — good balance of quality and size, 30-60% reduction. Suitable for most uses.
- High — maximum compression, 50-80% reduction. Best for email and web sharing where file size matters most.
What gets compressed
Images are downsampled to a lower resolution and re-compressed — this produces the biggest size savings since images often account for 80-95% of a PDF's file size. Embedded fonts may be subsetted (only the characters used in the document are kept). Duplicate objects are merged. Unused metadata and document history are stripped. Text and vector graphics remain unchanged.
Frequently asked questions
Will compression affect text quality?
No. Text in PDFs is stored as vector data (mathematical descriptions of each character), not as images. Compression does not alter text — it remains sharp at any zoom level. Only raster images (photographs, scanned pages) are affected by compression. If your PDF is entirely text-based, compression may achieve only modest size reduction.
How much can a PDF be compressed?
It depends on the content. PDFs full of high-resolution photos (like photo albums or scanned documents) can often be reduced by 70-90%. Text-heavy PDFs with few images may only be reduced by 5-20%. Already-compressed PDFs (from a previous compression tool) will show minimal further reduction. The tool shows the exact savings after processing.