PDF圧縮

Compress PDF files without sending them anywhere

This tool helps you compress PDF documents that are too heavy to email or upload. It works on the parts of a PDF that are actually big: the photos, scans and screenshots embedded in the pages. Each one is scaled down to a sensible size and stored as a smaller JPEG, while text, fonts and vector drawings are left exactly as they were.

Because the work happens in your browser, a 40 MB scan doesn't need to travel to a server and back. You get the result as fast as your computer can process it, and the document never leaves your hands.

How to compress a PDF

It takes four steps, and most files finish in a few seconds.

1. 1

   PDFをアップロード

   PDFをアップロードエリアにドロップまたは参照。250 MBまで、100ページまで受け付け。

2. 2

   品質プリセットを選択

   最小ファイルにはScreen、バランスのデフォルトにはeBook、高解像度画像にはPrint/Prepress。

3. 3

   PDFを圧縮

   「PDFを圧縮」を押します。圧縮はブラウザ内で行われるため、非常に大きな文書は低速な端末で少し時間がかかる場合があります。

4. 4

   縮小ファイルをダウンロード

   準備ができたら、縮小したPDFをダウンロードします。

What the four presets do

Each preset sets two limits for the pictures inside your PDF: the longest edge in pixels and the JPEG quality used to save them.

If an image would come out bigger than it already is, the original is kept. And if nothing in the file gets smaller, you get your original PDF back rather than a pointless copy.

Compress PDF to 1MB, 500KB, 300KB, 200KB, 100KB or 50KB

Job portals, university admissions and government sites often cap PDF uploads at a fixed size. In India, 200 KB, 300 KB and 500 KB limits are common for certificates and mark sheets. How close you can get depends on how many pages you have and how much of each page is a scanned image.

The rebuild method for very small limits

When a preset can't reach the number you need, rebuild the document from lighter page images:

• Turn each page into an image with PDF to JPG at 72 or 150 DPI.
• Shrink the images with Compress Image, using a target size per page (for a 200 KB, two-page PDF, aim for about 90 KB each).
• Put them back together with JPG to PDF. The JPEGs are placed into the PDF as they are, so the final size is close to the sum of the images.

The trade-off is that the pages become pictures, so the text can no longer be selected or searched. For certificates and ID scans that's rarely a problem.

Why some PDFs shrink a lot and others don't

• Scanned documents are a stack of full-page photos. They often drop by 70–90%, because scanners save pages at high resolution.
• PDFs with photos, such as brochures, menus and property listings, usually shrink by half or more.
• Text-only PDFs from Word or Google Docs are mostly fonts and text. They're already compact, so expect little or no change.
• Already compressed PDFs have little left to give. Compressing the same file twice rarely helps.
• Phone camera scans from apps that save each page as a 12-megapixel photo are the best candidates of all. The Screen and eBook presets bring those pages down to a size that still reads comfortably on any screen.

Get a smaller file before you even compress

A few habits upstream save more space than any preset:

• Scan at 150 or 200 DPI, not 600. For on-screen reading and most upload forms, 600 DPI only multiplies the file size.
• Scan in grayscale when color doesn't matter. Bank statements and printed letters look the same and take less room.
• Export instead of printing to PDF. In Word, Google Docs or LibreOffice, use Save as PDF or Export. Printing to a virtual PDF printer often embeds pages as large images.
• Remove pages you don't need before uploading. Dropping a blank back page from a scan cuts the size of a two-page file nearly in half.

Limits and privacy

You can compress PDF files of up to 250 MB and 100 pages. Password-protected files need their password removed first. Links, bookmarks and form fields usually survive because the document structure is kept, but always open the result before sending something important.

Nothing is uploaded. The PDF is read, rewritten and handed back to you inside your browser tab, with no account, no watermark and no copy kept anywhere. Need to combine files after compressing? Use Merge PDF.