How to Compress a PDF Online (Free)
Quick answer
Open PDFTeq's Compress PDF tool, upload your file, pick Screen / eBook / Printer, and download the result. It processes on our server using GhostScript — how much smaller it gets depends entirely on your file's content, especially how many images it has.
What actually makes a PDF smaller
Three things, roughly in order of impact:
- Image downsampling — the biggest factor by far. A scanned page saved at 300+ DPI is much larger than it needs to be for on-screen reading; reducing to 72–150 DPI shrinks it dramatically. Vector text and shapes aren't affected.
- Recompressing images — re-encoding embedded photos more efficiently, without changing their resolution.
- Structural cleanup — removing redundant objects and metadata. This saves a little, not a lot, on its own.
This is why a text-only report shrinks far less than a stack of scanned, photographed pages — there's simply less image data to optimize.
The three presets, honestly explained
PDFTeq's Compress tool uses GhostScript's standard -dPDFSETTINGS presets:
| Preset | Approx. image DPI | Best for |
|---|---|---|
| Screen | ~72 | Smallest file, on-screen only viewing |
| eBook | ~150 | Email, general sharing — the default |
| Printer | ~300 | Documents that will be printed |
We're not going to promise a fixed "70%" or "60%" number — depending on your specific file, results can land well outside those ranges in either direction. If you want a number, run it and see; it takes seconds.
Step-by-step
- Open the Compress PDF tool and upload your file (up to 200MB).
- Pick a preset — eBook is a reasonable default if you're unsure.
- Click Compress. The file is processed on our server and typically takes 10–30 seconds.
- Download the result and compare the before/after size shown on screen.
Is it private?
Be clear-eyed about this: this tool uploads your file to our server for GhostScript processing, transferred over HTTPS. Unlike some competitors that disclose a retention window of a few hours before auto-deletion, this file is deleted immediately after the compressed result is sent back to you — in the same request, with nothing left sitting on a server afterward. That's still a genuine upload, though, not the same privacy model as a truly client-side tool. If you specifically need processing that never leaves your device, that's a different category of tool — check what a provider's own technical description says, not just its marketing tagline.
If your document is regulated (medical, financial, legal), server-side processing may or may not meet your organization's requirements — that's a question for your compliance team, not something any tool's FAQ page can settle on your behalf.
PDFTeq vs. other compressors
| Tool | Processing | Sign-up | Notes |
|---|---|---|---|
| PDFTeq | Server (GhostScript) | No | Three fixed presets, no custom DPI control |
| PDF24 | Server (cloud) | No | Also offers an installable desktop app |
| Smallpdf | Server (cloud) | No (free tier) | Free tier compression level limited; more control on paid plans |
| iLovePDF | Server (cloud) | No | Similar free-tier model to Smallpdf |
| Adobe Acrobat | Server (web) / local (desktop app) | Yes | Desktop app processes locally; web version uploads |
Exact limits and pricing change over time — check each provider's current page rather than relying on any comparison table, including this one, for anything decision-critical.
What this tool doesn't do
- No password-protected file support — unlock the PDF first.
- No custom DPI or JPEG-quality slider — just the three GhostScript presets.
- One file per run — no batch upload.
Frequently asked questions
Is my file uploaded to a server?
Yes — this tool uses server-side GhostScript, transferred over HTTPS and deleted immediately after the compressed result is returned, in the same request.
How much smaller will my PDF get?
It depends on content — image-heavy scans shrink the most, text-only documents the least. There's no fixed percentage we can promise upfront.
Will compression make my text blurry?
No — text stays vector-based and sharp; only embedded images are downsampled.
Can I compress a password-protected PDF?
Not currently — remove the password first, then compress the unlocked file.
Is this GDPR or HIPAA compliant?
We can describe what technically happens to your file; whether that satisfies your specific regulatory obligations is a question for your compliance team.