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Compress PDF Online

Reduce PDF file size up to 90% online for free — perfect for email, uploads, and storage.

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Maximum file size: 50 MB

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1 Select PDF
2 Compress PDF
3 Download Compressed PDF

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How to compress PDF

  1. Upload one PDF file (up to 200 MB).
  2. Choose a compression level or pick a target file size.
  3. Click 'Compress PDF' — compression finishes in a few seconds.
  4. Download the compressed PDF.

Quick fact about PDF

A PDF scanned at 300 DPI can shrink from 10 MB to under 1 MB when re-compressed at 150 DPI — which is still readable for most document viewing. The size reduction depends heavily on whether the PDF contains raster images or just text.

Why compress PDF?

PDF files from scanners, cameras, or print exports are often 10-50x larger than necessary. A 5-page scanned document can be 15 MB when the same content fits in 500 KB. Compressing PDF saves storage, gets attachments under Gmail's 25 MB limit, and meets strict upload requirements for government portals, exam forms, and job applications.

Technical details

Input format PDF 1.4 to 2.0
Output format PDF
Typical reduction 40-90% for scanned PDFs, 5-30% for text PDFs
Text preservation Lossless (text/vector content preserved)
Image compression Lossy (raster images re-encoded)
Password-protected PDFs Not supported
Max file size 200 MB per PDF
File retention Auto-deleted after compression

How the conversion works

The compressor analyzes the PDF structure, then optimizes embedded images (raster content) by re-encoding them at lower resolution or higher compression. Text and vector content is preserved losslessly. Scanned PDFs (image-only) shrink the most; text-based PDFs (e.g. from Word) may shrink very little because their content is already efficient.

When to compress PDF

Quality considerations

Text content in the PDF is preserved losslessly — even at Maximum compression, text remains crisp because it is not raster. Only embedded images are re-encoded with quality loss. For scanned documents, quality matters more: below 150 DPI, text may become hard to read.

Limitations and caveats

Compatibility

Tips for best results

Compression levels explained

Level Size reduction Best for
Low (90% quality) ~20-40% Printing, archival
Medium (75% quality) ~50-70% Email, general use
High (60% quality) ~70-85% Strict size limits, web uploads
Maximum (40% quality) ~85-90% Extreme size limits, thumbnails

Target a specific file size

Need to hit an exact size? Use our dedicated target-size tools:

Common problems and fixes

Compressed PDF is barely smaller than the original
The PDF is likely text-only (from Word, Google Docs, or LaTeX). Text PDFs are already efficient — 5-30% is typical. Try Maximum compression, or check if there are high-resolution images embedded that could be downsampled.
PDF upload rejected — file too large even after compression
Use the target-size presets (e.g. 100KB) which force aggressive compression. For portals with 1 MB limits, consider splitting the PDF into multiple documents.
Text becomes blurry or unreadable after compression
The source PDF was a scan (image-based, not text-based). Use a lower compression level (Low or Medium) to preserve readability. Scanned text needs at least 150 DPI to stay legible.

Frequently asked questions

How much smaller will my PDF be? +
Scanned PDFs typically shrink 40-90%. Text PDFs shrink 5-30%. The result depends entirely on what the PDF contains.
Will text remain readable? +
Yes. Text and vector content is preserved losslessly — only embedded images are re-encoded. At Medium or Low compression, text is identical to the original.
Is it safe to compress PDF? +
Yes. We use industry-standard PDF optimization. Files are auto-deleted after compression.
Does compression remove PDF features? +
No. Bookmarks, links, annotations, and form fields are preserved. Only embedded images are re-encoded.
Can I compress a password-protected PDF? +
No. Remove the password first, then compress. We do not process encrypted PDFs.
What's the maximum file size? +
200 MB per PDF. Larger files should be split into smaller documents first.
Will my scanned document stay readable? +
Yes at Low or Medium compression. Maximum compression may reduce scan readability for small text — test the output before uploading to strict portals.

Sources and references

Last reviewed: 2026-10-01