PDF圧縮オンライン

What this PDF compressor does

This tool takes a PDF you upload and rebuilds it so the file uses fewer bytes, mainly by re-encoding embedded images at a lower resolution. Text content stays readable because it is stored as vectors — most of the size savings come from photos, scans, and graphics inside the document.

Use it whenever a PDF is too large for email, a form upload, or cloud storage. If you need to combine several files before compressing, use Merge PDF. To turn pages into pictures instead, try PDF to Image.

Why reduce PDF file size?

• Email attachments. Most providers cap attachments, and a scanned contract or slide deck passes that cap quickly. A smaller PDF sends without bouncing.
• Portal and form uploads. Job applications, visa portals, and school systems often reject anything over a fixed number of megabytes.
• Faster sharing. A compressed PDF uploads and downloads quicker, which matters on slow or mobile connections.
• Storage and archiving. Making PDFs smaller means more documents fit in the same cloud or disk space.

Formats, limits, and privacy

Accepted upload: PDF only. Maximum size: 100 MB. Maximum pages: 100.

Limitations: Compression can soften images inside the PDF. Already-optimized files may shrink only a little. Jobs are queued, so results are not instant for every file.

Privacy: Processing runs on our servers only for your request. Files are discarded promptly after you download — we don't keep them as cloud storage. No account is needed and the result carries no watermark.