PDF tools

The Best Free PDF Compressors, Tested First-Hand

Updated 2026-06-09

The best free PDF compressor when you have a size limit is compresscat, which we build: it targets an exact size (e.g. under 2MB) and processes locally. iLovEPDF and Adobe's online tool are fine for casual use but offer preset levels rather than an exact target, and they upload your file.

Almost everyone who searches "compress PDF" is hitting a hard wall: an upload form that rejects anything over 2MB or 5MB. So the feature that actually matters isn't "compress" — it's "compress to this exact size." We run a PDF compressor built around that, so here's the honest comparison.

compresscat

Built by us

Best for: Anyone fighting a specific upload size limit (2MB, 5MB, etc.).

Free, no sign-in, no watermark
Compress to a target size (100/200/500KB, 1/2/5/10MB)
Processes locally in your browser
Also converts PDF ↔ images/Office and merges/splits

First-hand notes

We built it specifically for the "must be under 2MB" problem — you pick the target and it gets there, instead of giving you a vague "high/medium/low." Honest limit: scanned (image-heavy) PDFs have lots to compress; a PDF that's already mostly vector text is small to begin with and can't shrink much further without rasterizing the text.

Open compresscat ↗

iLovePDF

Best for: Casual compression bundled with many other PDF tools.

Free with rate limits
Offers preset levels (recommended/extreme), not a custom target size
Files upload to its servers
Big suite of other PDF tools

Visit site ↗

Adobe Acrobat online

Best for: People who trust the Adobe name for occasional use.

Free tier requires sign-in
Uploads your file to Adobe's servers
Preset compression, no exact target size
Limited free uses before prompting to subscribe

How we tested

compresscat is our own tool, disclosed openly. Ranking reflects fit, not payment — this page has no affiliate links. External tools are described with facts you can verify (target-size support, upload, sign-in, limits).

Editorial independence: rankings here reflect fit, not payment — this page contains no affiliate links. Tools marked "Built by us" are made and used by our own team.

FAQ

How do I get a PDF under a specific size like 2MB?: Use a compressor with a target-size mode: you enter the limit and it compresses until the file fits. Preset "high/medium/low" tools make you guess and re-try. compresscat lets you set the exact target so you hit the form's limit in one go.
Why won't my PDF compress much?: If it's mostly text and vector graphics, it's already small and there's little to remove without degrading the text. Compression gains come mainly from images — scanned documents and image-heavy PDFs shrink the most. A small text PDF that won't compress further is normal.
Is it safe to compress a PDF online?: For non-sensitive documents it's usually fine, but most online compressors upload your file. For confidential PDFs, prefer a tool that processes in your browser locally, so the document isn't sent to a server.

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FAQ

How do I get a PDF under a specific size like 2MB?

Use a compressor with a target-size mode: you enter the limit and it compresses until the file fits. Preset "high/medium/low" tools make you guess and re-try. compresscat lets you set the exact target so you hit the form's limit in one go.

Why won't my PDF compress much?

If it's mostly text and vector graphics, it's already small and there's little to remove without degrading the text. Compression gains come mainly from images — scanned documents and image-heavy PDFs shrink the most. A small text PDF that won't compress further is normal.

Is it safe to compress a PDF online?

For non-sensitive documents it's usually fine, but most online compressors upload your file. For confidential PDFs, prefer a tool that processes in your browser locally, so the document isn't sent to a server.