Compress PDF
Reduce PDF file size while maintaining quality
Compress PDF reduces file size by optimizing embedded images and removing redundant data, so a PDF that's too large to email or upload becomes small enough to share — while text stays sharp and pages stay legible.
Text and vector graphics are never touched, so text stays selectable and sharp at every level. Lossless only tidies the file structure. Recommended re-encodes embedded photos at high quality. Smallest also reduces image resolution further, with slight softening only visible when zoomed in.
Choose a PDF file above — processing starts automatically.
How to use Compress PDF
- 1
Upload the PDF you want to shrink.
- 2
Pick a compression level — lighter for maximum quality, stronger for the smallest possible file.
- 3
Click "Compress PDF" and let it process.
- 4
Download the smaller file and compare the size reduction shown on screen.
Everything you need to know about compressing PDFs
What does "compressing" a PDF actually change?
A PDF's file size is almost always dominated by its embedded images, not its text — a page of plain text is a few kilobytes, but a single high-resolution scanned page can be several megabytes on its own. Compression works mainly by re-encoding those embedded images at a lower resolution or quality, which is why a scanned document typically shrinks far more than a text-only PDF exported from Word.
When you actually need this
- Email attachment limits — most providers cap attachments around 20–25MB.
- Application/portal upload limits — government and HR portals often cap uploads at 5–10MB.
- Storage and bandwidth — smaller files download faster and take up less space when archived.
Choosing a compression level
| Level | Best for |
|---|---|
| Lossless | Documents where nothing visible may change: contracts, forms, anything going to print |
| Recommended | Most cases — strong size reduction with high visual quality |
| Smallest | When file size matters most (e.g. a hard 5MB upload cap): images are reduced further, text stays sharp |
What actually determines a PDF's size
- Embedded images — by far the biggest factor, especially scanned pages saved at high DPI.
- Embedded fonts — a document using many custom fonts carries their full font data.
- Number of pages — obviously scales file size, but far less than image resolution does.
Keeping files small from the start
If you're the one creating the original document (not just compressing someone else's), scanning at 150–200 DPI instead of 300+ for anything that isn't a photograph avoids the problem entirely — most scanning apps default higher than necessary for a document that's only going to be read on a screen.
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Frequently Asked Questions
How much smaller will my PDF get?
It depends on the content — PDFs with large images typically shrink 40–80%, while text-only PDFs are already small and compress less dramatically.
Will compression make my PDF blurry?
Text and vector content stay crisp regardless of the setting. Embedded photos are re-optimized — the higher compression levels trade a small amount of image detail for a much smaller file.
Can I compress a password-protected PDF?
Unlock it first with the Unlock PDF tool, then compress it — encrypted files can't be re-processed directly.
What actually makes a PDF large in the first place?
Embedded images almost always dominate — especially scanned pages saved at high resolution. Embedded fonts and page count matter too, but far less.
Which compression level should I pick?
Recommended for most cases. Text stays selectable and sharp at every level. Use Lossless if no image may change at all; use Smallest only when you're up against a hard size limit, like a 5MB upload cap.
Is my data safe when using this tool?
Yes. Files are processed securely and deleted from our servers within 1 hour.