boxtool.io

PDF Compressor

Reduce PDF file size without losing quality. Three compression levels. Runs in your browser — no upload, free.

Drop PDF here or click to browse

Supports PDF files

About PDF Compressor

The PDF Compressor reduces the size of PDF files using three configurable compression levels — light, balanced, and aggressive — all running locally in your browser. No files are uploaded to a server. Ideal for meeting email attachment limits, portal upload restrictions, or just making files more shareable.

Use Cases

  • Shrink a large PDF to fit within an email attachment size limit
  • Compress scanned documents before uploading to a government or HR portal
  • Reduce the size of a PDF portfolio for web distribution or client sharing
  • Batch-compress invoices, contracts, or reports for efficient archiving

Tips

  • Balanced compression usually offers the best quality-to-size trade-off for most documents
  • Images embedded in PDFs benefit most from aggressive compression — text is unaffected
  • For text-heavy PDFs without images, use light compression to preserve maximum quality

Frequently Asked Questions

The compressor re-encodes images inside the PDF at lower quality and applies stream compression. Text and vector graphics are not affected — only embedded bitmap images are reduced.

Low: fastest, minimal size reduction, highest image quality. Medium: balanced (recommended for most documents). High: maximum size reduction, lower image quality.

No. All compression happens entirely in your browser using PDF-lib. Your file never leaves your device.

PDFs that contain mostly text and vector graphics have very little image data to compress. Size reduction only applies to embedded raster images.

Password-protected PDFs cannot be processed — you will see an error. Standard PDFs (including PDF/A) work fine.

There is no enforced limit — the tool is bounded only by your browser memory. For most documents (under 100 MB), compression completes in a few seconds.

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