PDF圧縮
画質を最適に保ちながらファイルサイズを縮小します。
About Compress PDF
How PDF Compression Works
The tool renders each page as an image at a controlled resolution and quality level, then rebuilds the PDF from those optimized images. Lower DPI and JPEG quality mean smaller files. Higher settings preserve more detail. You choose the balance.
OxygenPDF offers four presets — Light, Balanced, Maximum, and Extreme — plus a target-size mode where you set the exact file size you need and the tool figures out the right settings automatically.
Why Compress a PDF
File size caps are everywhere. Email attachment limits, upload forms, cloud storage quotas. Compression gets you under the line.
Email Attachments
Most email providers cap attachments at 25 MB. A 40 MB report won’t send. Compress it to fit.
Web Uploads
Job applications, government forms, and insurance portals often limit uploads to 5–10 MB. Compression gets large scans under the limit.
Faster Sharing
Smaller files transfer faster over slow connections, load quicker in browsers, and take up less space on shared drives.
Storage Savings
Archiving hundreds of scanned PDFs? Even moderate compression cuts storage needs in half.
Four Presets and a Target-Size Mode
Light compression (200 DPI, 85% quality) typically reduces file size by 30–40%. Good for printing. Balanced (150 DPI, 75% quality) hits 50–60% reduction — the sweet spot for most uses. Maximum (100 DPI, 60% quality) pushes 70–80% reduction for screen-only viewing. Extreme (72 DPI, 35% quality) gets 85–95% reduction when every kilobyte counts.
Target-size mode flips the process. Enter the maximum file size in MB, and the tool samples representative pages to find the best compression level that fits. It runs a binary search across quality settings so you get the highest quality that meets your constraint.
How It Compares
Compression is a standard feature, but the controls and privacy model differ.
| 機能 | OxygenPDF | Adobe Acrobat | iLovePDF |
|---|---|---|---|
| Multiple compression presets | |||
| Target-size mode | |||
| Grayscale conversion | |||
| Custom DPI and quality sliders | |||
| Real-time size estimate | |||
| No file upload required | Desktop only | ||
| Free to use | Limited |
Your PDF Stays on Your Device
Online compressors upload your file, process it on their servers, and send back the result. Your document passes through infrastructure you don’t control. For personal documents, financial records, or anything under NDA, that’s a risk.
OxygenPDF compresses in your browser. The file never leaves your machine. Close the tab and the data is gone.
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