压缩 PDF
Reduce the file size of your PDF while maintaining optimal visual quality for uploads and email attachments.
选择 PDF 文件
or drag and drop PDF here
PDF 压缩与流优化算法深度指南
PDF files can become bulky when they contain high-resolution images, embedded fonts, and complex vectors. Compressing a PDF involves optimizing these assets to reduce file size without compromising readability.
Lossless vs. Lossy PDF Optimization
PDF compression uses two main methods: lossless and lossy. Lossless compression shrinks text streams using algorithms like FlateDecode (Deflate). Lossy compression targets raster images embedded in the document, compressing JPEG data or downsampling images (e.g. from 300 DPI to 150 DPI) to dramatically reduce file sizes.
The Security Advantage of Local Compression
Because PDFs often contain financial statements or confidential records, uploading them to public cloud servers for compression poses privacy risks. DocumentAlter compresses PDFs directly in your browser, keeping your sensitive documents secure.
如何压缩 PDF 文件（分步操作指南）
Import Target PDF File
Select or drag the PDF document you want to optimize into the compression area.
Configure Optimization Strength
Choose your compression level: Recommended (best quality/size ratio), Extreme (maximum size reduction), or Low.
Optimize and Download
Run the local optimization script to re-compress the document and download the smaller file.
常见问题解答
将文件拖入 DocumentAlter 的 "压缩 PDF" 工具中，选择适合的压缩档位，点击 "压缩 PDF" 即可下载精简优化的文件。
不会。算法采用智能流重构与冗余数据去重技术，在消除无用元数据与优化字体的同时，完整保留文本与图像的高清质感。
绝对安全。所有压缩计算均在浏览器的隔离沙箱中运行，机密商务文件与私人数据绝不经过互联网传输。