You try to attach a document to an email and get the dreaded message: "Attachment size exceeds the allowable limit." Gmail caps attachments at 25 MB, Outlook at 20 MB. A report, contract, or invoice can easily exceed these limits. Fortunately, compressing a PDF takes under 30 seconds with the right tool.
Why are PDFs so large?
A PDF can contain high-resolution images, embedded fonts, metadata, and unnecessary layers that significantly increase its file size without improving on-screen quality. A scanned document often produces a file of 5 to 15 MB, while the compressed version stays under 500 KB — with no visible loss of readability.
Smart compression analyzes every component of the file: it reduces image resolution to screen-appropriate levels (72–150 dpi instead of 300 dpi), removes redundant streams, and cleans up orphaned objects. The result is a much lighter file that remains perfectly readable and printable.
The 100% local and private method
Most online compressors upload your PDF to their servers, process it, then send back the result. This creates a real privacy issue: your invoices, contracts, or medical documents travel through third-party infrastructure whose data retention policies you don't control.
Our tool works entirely within your browser using WebAssembly technology. Your file never leaves your computer. Compression happens locally, guaranteeing absolute confidentiality and optimal speed — you don't even need a fast internet connection to process your file.
Steps to compress your PDF in under a minute
The process is intentionally simple: open the compression tool, drag and drop your file or click to select it, choose the compression level (high, medium, or low based on your needs), then download the lighter file. No sign-up, no account to create, no hidden size limits.
You can compare the before/after size directly in the interface. In most cases, "high" compression reduces a PDF's weight by 60 to 80% while maintaining perfect readability. A 10 MB file often becomes a 1.5 to 2 MB file — well below email attachment limits.
Tips to further optimize your email attachments
If your PDF contains many full-page images, opt for "medium" compression to keep acceptable print quality. For text-heavy documents with few illustrations, "high" compression works perfectly. You can also split a very large PDF into multiple parts before compressing them individually, then merge them back if needed.
Always keep the original high-resolution version on your hard drive. Send the compressed version by email, but archive the original for any professional use (printing, legal archiving, etc.).