Alttoalternative to
Convert a PDF Tools
Free · No sign-up · Runs in your browser

Shrink a PDF's file size.

Recompresses the photos and scanned pages inside your PDF so the file is smaller and easier to email or upload — your text stays sharp, selectable, and exactly where it was.

Not uploaded — nobody sees it Text and layout untouched No watermark, ever No subscription or account
Compression level
Your PDF is never uploaded — it’s processed right here in this browser tab, on your device. There’s no server involved, so we never see it, copy it or keep it.
How it works

Three steps, no waiting on a server

Altto's compress tool recompresses your file right in your browser tab, so there's no upload queue and no "processing your file" spinner tied to someone else's servers.

01

Add your PDF

Drop in the file you want to shrink and pick a compression level.

02

Photos and scans are recompressed

The embedded images are re-encoded at a lower quality, entirely on your device. Text and layout aren't touched.

03

Save the smaller PDF

See exactly how much smaller it got, then download the result.

Why this runs in your browser, not on a server

The PDFs people need to shrink are often the ones they're about to email or upload somewhere — the last thing they need is a detour through a stranger's server first. Altto skips that entirely.

  • Nothing is uploaded, everEvery PDF is handled by code that runs in this browser tab, because there’s no server on the other end. That also means we can’t see it, copy it or keep it.
  • Text stays textOnly embedded photos and scans are recompressed — your document is never flattened into images.
  • You see the result before you commitThe exact size saving is shown before the download starts, so there are no surprises.
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documents stored on our servers. There’s no server involved at all — the smaller PDF is built once, then everything happens locally.

FAQ

Frequently asked questions

The practical details on what this tool can and can't do. Need to combine files instead, or turn a PDF into Word? See our other guides and tools.

How does this make my PDF smaller?
It recompresses the photos and scanned pages embedded inside your PDF at a lower quality level. Text, fonts and vector graphics are left exactly as they are, so your document stays sharp and searchable.
Will my text still be selectable and searchable afterwards?
Yes. This tool never turns your pages into flat images — it only targets the embedded photos and scans, so any real text in your PDF stays exactly as selectable and searchable as before.
What's the difference between the three compression levels?
Less compression keeps image quality closest to the original with a modest size saving. Recommended lowers image quality slightly for a solid size reduction with almost no visible difference. Smaller file also reduces very high image resolutions down to a more typical screen size, which shrinks the file further but can be noticeable if you zoom in a lot.
Why didn't my PDF get much smaller?
If a PDF is mostly text, or its images are already compressed or in a format this tool doesn't touch, there may not be much room left to shrink. You'll always be shown exactly how much was saved before you download.
Is my file uploaded anywhere?
No — nothing is ever uploaded. Your PDF is opened and recompressed entirely inside this browser tab. There's no server involved at all, so there's nothing for Altto to see, copy or keep.
Can I compress a password-protected PDF?
Not directly — a locked PDF needs to be unlocked first. Use our Unlock PDF tool to remove the password, then compress it here.
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