# Compress a scanned PDF — shrink for email, no upload

> Re-encode scanned pages to smaller JPEGs and control the quality so an email-friendly PDF stays readable. All the work happens on your device, with no upload.

Re-encode scanned pages to smaller JPEGs with a quality control you set, so a heavy scan becomes an email-friendly PDF that's still readable. The compression runs on your device, so the file isn't uploaded to shrink it.

Scanned PDFs are notorious email bouncers because every page is a big image. Compressing re-encodes those images to a size that actually sends, and giving you the quality dial means you decide the trade-off rather than a server deciding for you.

The black & white filter pairs well here: text-only pages compress especially hard once they're clean high-contrast images. For color documents, a moderate quality keeps them legible while still shedding most of the weight.

Apply Scan filters first for the best ratio, finish with Build PDF, and for compressing a general (non-scan) PDF use the Document Desk's Compress.

## How to

1. **Load the scan.** Use your scan session or a scan-heavy PDF.
2. **Set quality.** Choose a quality level to trade size against sharpness.
3. **Compress.** Pages are re-encoded to smaller JPEGs locally.
4. **Download.** Save the lighter PDF.

## FAQ

### Why are scanned PDFs so large?

Each page is a full-resolution image, so a few pages balloon into many megabytes. Re-encoding those images at a sensible quality dramatically cuts the size.

### Will compression make my scan unreadable?

Not if you pick a reasonable quality — the control lets you find the point where text stays crisp but the file is small enough to email or upload.

### How small can it get?

It depends on content and quality setting, but scan-heavy PDFs commonly drop by a large margin, especially with the black & white filter applied first.

### Is my PDF uploaded to compress it?

No. Re-encoding happens in your browser, so even a confidential scan is compressed without leaving your device.


## Related tools

- [Scan filters](https://www.safepaper.app/scan/filters)
- [Build PDF](https://www.safepaper.app/scan/to-pdf)
- [Compress](https://www.safepaper.app/docs/compress)
- [Scrub & redact](https://www.safepaper.app/scan/scrub)

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