How does PDF compression work?

The tool renders each PDF page using PDF.js and re-encodes it as a compressed JPEG image, then rebuilds the PDF with pdf-lib. This significantly reduces file size for image-heavy PDFs.

What compression levels are available?

Screen (72 DPI) produces the smallest file and is suitable for web or email. eBook (150 DPI) balances size and quality. Printer (300 DPI) preserves more detail but produces a larger file.

Will text remain selectable after compression?

No. The current compression method re-renders pages as images, so text will not be selectable in the output PDF. This is a trade-off for maximum compression.

Is there a file size limit?

There is no enforced limit, but large PDFs with many pages may take a while to process in the browser.

Are my PDFs uploaded to a server?

No. All compression is done client-side in your browser. Your files never leave your device.

How much can I reduce a PDF's file size?

Results vary depending on the PDF content. PDFs with many high-resolution images can be reduced significantly. Text-only PDFs have less room for compression.

Will compression reduce PDF quality?

Image compression may slightly reduce image quality at higher compression levels. Text and vector graphics are not affected.

Is my PDF sent to a remote server for compression?

No. Unlike most online PDF compressors that upload your file to a cloud service, our tool processes everything inside your browser using pdf-lib. Your document never leaves your device.

Compress PDF — Reduce PDF File Size Free Online

Reduce PDF file size by compressing embedded images and streams. Free online PDF compressor — no upload required.

Click to upload or drag & drop

PDF files up to 50MB

100% Private

No Upload

Instant

What is Compress PDF — Reduce PDF File Size Free Online?

A PDF compressor reduces the file size of PDF documents by compressing embedded images, removing redundant data, and optimizing internal streams. Large PDFs are difficult to email, upload, or share. Our PDF Compressor runs entirely in your browser using pdf-lib — your files are never uploaded to any server.

How to Use Compress PDF — Reduce PDF File Size Free Online

1Upload your PDF file by clicking or dragging onto the tool.
2Select the compression level.
3Click Compress.
4Download the compressed PDF.

Key Features

Compresses embedded images
Multiple compression levels
Runs in your browser using pdf-lib
No file size limits imposed by the tool

Benefits

Email large PDFs that exceed attachment limits
Upload PDFs to platforms with file size restrictions
Reduce storage space for PDF archives

Use Cases

Compress PDF for email Compress under 1MB Compress PDF free guide

Why Use Irreva for Compress PDF — Reduce PDF File Size Free Online?

Email large PDFs that exceed attachment limits

Upload PDFs to platforms with file size restrictions

Reduce storage space for PDF archives

Runs 100% in your browser — files never leave your device.

No account, no sign-up, no subscription — free forever.

Works on any device: desktop, tablet, or mobile.

Frequently Asked Questions

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