Compress PDF
Reduce file size by lowering image quality / scaling pages.
點選或拖拽 PDF 到這裡
上傳要壓縮的 PDF
壓縮級別
頁面縮放
💡 壓縮透過降低頁面圖片清晰度實現，純文字型 PDF 體積變化不大；深度壓縮適合掃描件，但會明顯降低畫質。
How to use
This tool belongs to the “Watermark & optimise” category.
- 1Watermarks can be text or image: text takes content, font, size and colour, while an image watermark can be tiled or angled.
- 2Page numbers support Page {num}, {num} / {total} or a bare number, with font, size, footer and side margins, and mirrored odd and even pages.
- 3Compression trades image sharpness for size. Try one level first: text-only PDFs shrink little, scanned ones shrink a lot.
Every PDF is handled in this tab by JavaScript. Files never leave your device and we keep no copy.
Frequently asked questions
Can I watermark or compress a protected PDF?
Sort out permissions first: "Decrypt PDF" works only on files whose open password you know, or on files that merely restrict printing and editing.
Does compression hurt quality?
It does - it re-encodes the images inside the page. Run the heavier setting to see the result, then back off if it is too aggressive.
Text became unselectable after decrypting.
That is expected: unlocking can convert the text layer into an image. If you need searchable text, run OCR over the result.