# Compress PDF Files

> Most PDF compressors upload your file. This one doesn't. Pick a quality preset (low / medium / high), watch the live size estimate update against the original, and save the smaller file when it looks right. Compression runs in the browser via pdf-lib, so an 80 MB tax return or a draft contract never lands on someone else's server. The math is the same as Smallpdf or iLovePDF; the upload round-trip isn't there.


Live tool: https://lofttools.com/tools/pdf-tools/compress-pdf

Category: PDF & Documents


## What it does

- Three quality presets — low, medium, high
- Live size estimate updates against the original before download
- Image stream re-encoding (JPEG quality + downsampling tuned per preset)
- Font subset re-encoding to drop unused glyphs
- Bookmarks, hyperlinks, form fields, and annotations preserved through compression
- PDF/A flag preserved when input is PDF/A
- pdf-lib backed, runs in the browser tab
- No file size limit beyond what the browser can hold in memory
- Multi-page PDFs supported in a single pass

## How it works

1. **Select PDF** — Drop the PDF you want to shrink, or click to browse
2. **Choose quality** — Select compression level — high, medium, or low
3. **Download** — Get your compressed PDF instantly

## FAQ

### What is the maximum file size?

Up to 100MB per file. Premium users can process larger files.

### Does this preserve bookmarks and form fields?

Yes. Compression rewrites image streams and re-encodes fonts, but bookmarks, hyperlinks, form fields, and annotations carry over to the smaller file.

### What PDF versions are supported?

PDF 1.0 through 2.0. The output PDF version follows the input; downgrades are not performed.

## Privacy

This tool runs entirely in the browser. Files are not uploaded to a server. They never leave the user's device.

## More

- All tools: https://lofttools.com/tools
- Category: https://lofttools.com/tools/pdf-tools
- LLM index: https://lofttools.com/llms.txt