Compress PDF

Reduce PDF file size with private browser compression.

Drop one PDF here, or click below to compress it.

Choose PDF

100% secure · GDPR Compliant

Bank-grade security & 100% privacy

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Up to 90%

PDF size reduction possible

100%

On-device compression

Free

No account required

How it works

Start in 3 easy steps

A quick visual tour of the private PurePDF workflow.

Upload your PDF

Drop the large PDF you want to shrink.

Choose compression

Select a quality level or custom reduction target.

Export optimized file

Queue the compressed PDF in the download hub.

Designed for private PDF work

Fast, clear, and built around local browser processing.

Local compression

Ghostscript runs in your browser so sensitive files stay private.

Choose the savings

Pick light, balanced, extreme, or a custom compression target.

Download ready

Optimized PDFs go straight to the download hub with size metadata.

Try our complete PDF toolkit

Every PurePDF tool, organized by what you need to do.

Convert to PDF

Edit

Organize

Review

Frequently
Asked
Questions

Quick answers about this PurePDF workflow.

Is the PDF compressor really free?

Yes. PurePDF Compress PDF is 100% free with no account required, no watermarks, and no file limits for standard use.

Do my files get uploaded to a server?

No. Compression runs entirely in your browser using WebAssembly. Your PDF never leaves your device.

How much can I reduce my PDF file size?

Typically 40–90% depending on content. Image-heavy PDFs compress the most. Text-only PDFs compress less but still see meaningful reductions.

Can I compress a PDF without losing quality?

Yes. Use the "High Quality" or "Balanced" compression level to reduce file size while keeping text sharp and images visually clean.

Can I compress a PDF to under 1MB for email?

Yes. Use the "Extreme" compression level or set a custom percentage target to reach your desired file size, including under 1MB.

What is the maximum file size I can compress?

The free tier supports files up to 10MB. Pro ($7.99/mo) supports up to 100MB for larger documents.

Can I use this on my phone or tablet?

Yes. PurePDF works on any modern mobile browser including Chrome and Safari on iOS and Android.

Is this GDPR compliant?

Yes. Because your file never leaves your browser, there is no data transfer to any server — making it fully GDPR compliant by design.

Does compression affect the PDF text or fonts?

No. Text and fonts remain fully intact. Compression primarily targets embedded images and document metadata.

Can I compress multiple PDFs at once?

The free tool processes one PDF at a time. Batch compression is available on the Pro plan.

The complete guide to compressing PDFs

Why PDF file size gets out of hand

Most oversized PDFs have one culprit: images. A document scanned at high resolution, a report full of screenshots, or a brochure exported from design software can easily reach 20–50MB even when the text content is tiny. Email providers typically cap attachments at 25MB, government and job portals often enforce limits as low as 1–2MB, and messaging apps compress or reject large files. That gap between what tools produce and what platforms accept is why PDF compression is one of the most-used document operations in the world.

Compression works by re-encoding the images inside your PDF at a smarter quality-to-size ratio, downsampling resolution that no screen or printer will ever show, and stripping redundant metadata. Text and fonts are left untouched — which is why a well-compressed PDF looks nearly identical to the original at a fraction of the size.

How to get the smallest file without visible quality loss

PurePDF gives you three presets plus a custom target. For most documents, Balanced is the right choice: it typically cuts 50–70% of the file size with no visible difference on screen. Use High Quality when the PDF will be printed professionally, and Extreme when you must hit a hard limit like "under 1MB" for a government portal.

Compressing to a specific size? Use the custom target slider instead of guessing with quality levels — the engine iterates until it hits your number.
Scanned documents compress the most (often 80–90%), because scanner output is heavily over-resolved.
If a text-only PDF barely shrinks, it was already efficient — there is simply little left to remove.
Compress before merging, not after: smaller inputs make every downstream step faster.

Why compress with PurePDF instead of other tools

Unlike almost every competing service, PurePDF compression runs entirely in your browser using a WebAssembly build of Ghostscript — the same engine used in professional print workflows. Your file is never uploaded to a server, which means there is nothing to intercept, store, or leak. That makes it safe for contracts, financial statements, and medical documents that should never leave your machine.

There are also no artificial limits. Smallpdf caps free users at roughly two tasks per day; iLovePDF limits file sizes. PurePDF lets you compress as many PDFs as you want, every day, free, without watermarks or signup.

Troubleshooting common compression problems

If your compressed PDF looks blurry, you likely used Extreme on a document that will be read at high zoom — recompress the original with Balanced instead. If the file barely shrank, check whether it is mostly text (already efficient) or was previously compressed. And if the PDF is password-protected, unlock it first — encrypted files cannot be recompressed until the encryption is removed.