# Is it private and safe to compress a PDF online?

_Updated July 2026 · Arthize · https://arthize.com/answers/private-compress-pdf_

Yes. When you compress a PDF in Arthize, the file is processed inside your private workspace and deleted after the job — never sold or used to train models. PDF file size almost always comes from embedded images, not text.

## Answer

Yes. When you compress a PDF in Arthize, the file is processed inside your private workspace and deleted after the job — never sold or used to train models. PDF file size almost always comes from embedded images, not text.

## More about compress pdf

PDF file size almost always comes from embedded images, not text.

Down-sampling scans to a lower DPI usually gets an image-heavy file under 1MB.

Light compression is visually lossless for most documents.

## How to compress a PDF

1. **Open the compress tool** — Sign in and open the Compress tool.
2. **Add your PDF** — Upload the oversized file; it is processed privately.
3. **Pick a compression level** — Higher compression down-samples images more; light compression keeps them crisp.
4. **Download the smaller file** — Most image-heavy PDFs drop well under 1MB with no visible quality loss.

## FAQ

### How do I compress a PDF to under 1MB?

Compressing a PDF reduces file size — often 50–90% on image-heavy scans — by down-sampling images and stripping redundant data, while keeping text selectable. On Arthize it's free with no watermark and processed privately.

### Will compressing a PDF lose quality?

Compressing a PDF reduces file size — often 50–90% on image-heavy scans — by down-sampling images and stripping redundant data, while keeping text selectable. On Arthize it's free with no watermark and processed privately.

### How do I reduce PDF file size for email?

Compressing a PDF reduces file size — often 50–90% on image-heavy scans — by down-sampling images and stripping redundant data, while keeping text selectable. On Arthize it's free with no watermark and processed privately.