---
title: "Compress PDF Online — No Upload, 100% Private | Compress Pro"
description: "Reduce PDF file size right in your browser. Choose a preset or a target size like 2 MB. No uploads — documents never leave your device. Free & private."
canonical: https://compress-pro.com/compress-pdf
---

# Compress PDFs.

> Shrink PDFs in your browser — files are never uploaded.

Compress PDF files right in your browser — no upload, no waiting on a server. Pick a compression level or a target size like 2 MB — and merge PDFs, extract or remove pages, or convert between PDFs and images with the same tool. **Documents never leave your device.**

**No uploads · No ads · Free & open source.**

## How it works

1. Drop files anywhere on the page, click to browse, or paste with Ctrl/⌘ + V.
2. Pick a quality or preset — or set an exact target size and let the tool find it.
3. Compress, compare before/after, and download — individually or as a ZIP.

## Choosing a preset

Each preset trades image sharpness for size by downsampling the pictures inside the PDF — text always stays crisp, because it is vector data that costs almost nothing.

| Preset | Image resolution | Best for |
| --- | --- | --- |
| Low | 300 DPI | Archival copies and print — barely touched |
| Medium | 150 DPI | The all-round default: email, sharing, filing |
| High | 120 DPI | Web publishing and internal documents |
| Ultra | 72 DPI | Screen-only reading, big scans |
| Extreme | 50 DPI | When only the size limit matters |

## Common upload limits — and how to hit them

Most email providers cap attachments around 25 MB — and because attachments are re-encoded for transport, a file should really stay under ~19 MB to send reliably. Government portals, job applications and e-invoicing systems are stricter still, typically 2–5 MB per document.

Instead of guessing which preset gets you there, switch to target-size mode and type the limit itself (say 2 MB): the tool keeps trying stronger settings until the output fits, and tells you honestly if the target is impossible. If several documents must travel together, [merge them](https://compress-pro.com/merge-pdf) first and compress the combined file; if only a few pages matter, [split the PDF](https://compress-pro.com/split-pdf) and send just those.

## Scanned vs. text-only PDFs

Scanned documents shrink dramatically — every page is a photograph, so downsampling and re-encoding routinely cuts 80–90% of the size. Digitally created, text-only PDFs are already compact; if yours barely shrinks, it was efficient to begin with. Image-heavy presentations sit in between and respond very well to the Medium and High presets.

## Under the hood

Compression is done by Ghostscript — the PDF engine that has anchored print and publishing workflows for decades — compiled to WebAssembly and running locally, so a confidential contract gets professional-grade processing without ever touching a server. Merge, split and page extraction run on pdf-lib, and page previews render through pdf.js, the same PDF renderer Firefox uses.

## Frequently asked questions

### Is it safe to compress confidential PDFs here?

Yes — this is the point of the tool. Compression runs entirely on your own device; documents are never uploaded and no server ever sees them. Close the tab and nothing remains. Want proof? Run one document through, switch your connection off, and run another — it still works.

### How small can a PDF get?

It depends on what is inside. Scanned or image-heavy PDFs shrink dramatically because images are downsampled and re-encoded; text-only PDFs are already compact.

### Can I hit an exact size like 2 MB?

Yes — target-size mode tries increasingly strong settings until the output fits under your limit, ideal for portals that cap uploads.

### Is there a file size limit?

No hard limit — processing is bounded by your device’s memory. Very large files (200 MB+) work, they just take longer. There are no artificial limits either: no daily caps, no ads, no premium tier.

## Related tools

- [Convert PDF to JPG](https://compress-pro.com/pdf-to-jpg)
- [Convert JPG to PDF](https://compress-pro.com/jpg-to-pdf)
- [Merge PDF files](https://compress-pro.com/merge-pdf)
- [Zip & Unzip files](https://compress-pro.com/zip-files)

---

Part of [Compress Pro](https://compress-pro.com/) — every tool page has a markdown twin at `<page url>.md`. Full tool index: [llms.txt](https://compress-pro.com/llms.txt)