在线免费PDF优化器

Results vary widely by content: PDFs with many high-resolution images can be reduced 50–80%. PDFs that are mostly text compress 10–20%. Already-compressed PDFs may not reduce significantly. The tool shows the actual reduction before download.

Compression reduces image resolution and quality within the PDF, removes embedded duplicate fonts, and resamples high-DPI images down to screen-appropriate resolution. Text content and layout are not affected.

Text remains crisp at all compression levels — only embedded images are resampled. Light compression keeps images at 150 DPI; Maximum compression reduces to 72 DPI, acceptable for screen viewing but not for print.

Basic compression runs in the browser. For advanced compression (server-side image resampling), files are processed on temporary servers and immediately deleted after download — typically within 30 minutes.

Browser-based compression handles up to 50 MB. Server-side compression accepts files up to 200 MB. For larger files, use a desktop compression tool or Ghostscript from the command line.

Yes, the PDF优化器 on Allio Tools is completely free with no sign-up or registration required. It works directly in your browser.

通过删除元数据和优化文件结构来减小PDF大小，完全在浏览器中运行。 No data is sent to a server — everything runs locally in your browser for maximum privacy and speed.

No installation needed. The PDF优化器 runs entirely in your web browser on any device — desktop, tablet, or mobile.

Completely safe. The PDF优化器 processes everything locally in your browser. No input data, results, or usage information is ever transmitted to or stored on any server.

After the page loads for the first time, the PDF优化器 works without an internet connection for all client-side processing. Tools that fetch live external data (such as DNS or network lookups) require an active connection.

Yes. The PDF优化器 is fully responsive and works on all modern smartphones and tablets. No app download is required — open your mobile browser, navigate to the tool, and use it exactly as you would on a desktop.

Copy the result text or take a screenshot to share via message, email, or social media. The tool URL can also be bookmarked and shared directly — the PDF优化器 works for anyone with a modern browser, no account required.

Yes. The PDF优化器 is built with standard browser APIs and works on all modern browsers including Chrome, Firefox, Safari, and Edge — on both desktop and mobile. No plugins, extensions, or third-party software are required.

Select and copy the result text to paste into any document or app. For image tools, a Download button saves the file directly to your device. Your browser's built-in screenshot function also captures results quickly. No account or login is required.