Compress PDF file size
Reduce PDF file size while maintaining read quality. Everything runs securely in your browser with zero server uploads.
or drag and drop your document here
Zero Server Uploads
Standard online compressors transmit your sensitive documents across remote third-party servers. PDFMill processes every byte directly in your browser sandbox using WebAssembly, maintaining total document privacy.
Intelligent Downsampling
High-resolution embedded images and uncompressed metadata account for up to 90% of PDF bloat. Our bicubic resampling re-encodes raster assets to optimal screen DPI without degrading typography.
No File Size Limits
Because processing relies on your local device CPU and RAM rather than costly server clusters, PDFMill handles large multi-hundred-megabyte PDFs without subscription fees or artificial caps.
Frequently Asked Questions
How does client-side PDF compression work?
When you select a document, PDFMill parses the PDF structure locally using PDF.js and pdf-lib. It isolates heavy bitmap streams, resamples them to target resolution standards (such as 130 DPI for standard viewing or 96 DPI for extreme savings), and packs the resulting streams using object stream compression dictionaries.
Are my financial or confidential records safe?
Yes. You can verify this in your browser developer tools under the Network tab: no PDF data is ever dispatched over HTTP/WebSocket requests. This makes PDFMill fully compliant with internal corporate compliance, HIPAA, and GDPR document workflows.
What compression level should I choose?
Choose Recommended for business reports, resumes, and forms. Choose Extreme when submitting to email servers with strict 10MB or 25MB attachment limitations.