PDF圧縮

A PDF compressor reduces file size by re-rendering each page as an image at a quality you control, showing the before and after sizes so you can see exactly what you saved.

Compression runs entirely in your browser, so the file never leaves your device, which is important for the sensitive documents people most often need to shrink and send.

This approach shines on scanned and image-heavy PDFs, the kind produced by a scanner or a phone photo of a document, where the bulk of the file is picture data that compresses well at a slightly lower quality.

It is not magic for every PDF, though. A text-only PDF is already compact, so rendering its pages to images can leave the result the same size or even larger. If a compress does not help, that usually means the original was already efficient.

Because pages are flattened to images, the text is no longer selectable or searchable, and links and bookmarks are not preserved. Keep your original if you need any of those.

Pick a lower quality for a smaller file and a higher one to stay closer to the original, then compare the sizes before downloading so you can choose the balance you want.