Question 1

Are my files uploaded anywhere?

Accepted Answer

No. The compressor is Ghostscript compiled to WebAssembly, served from this site and run inside your browser tab. The page's security policy blocks it from sending data anywhere. After you have opened this tool once on this device, it keeps working without a connection.

Question 2

Which quality should I pick?

Accepted Answer

Balanced suits email and sharing. Smallest suits reading on screen. Print keeps images sharp enough for paper. Prepress keeps colour profiles for professional printing.

Question 3

Can I see how small the file will be before I save it?

Accepted Answer

Yes. Each choice shows the size and percentage it would give, measured on your device. For a very large file, the size is an estimate from its first pages.

Question 4

What do the More options do?

Accepted Answer

They give finer control than the four choices: picture sharpness in dpi, picture quality, grey instead of colour, and removing the title, author and other document details. They replace what the chosen quality would do, and the sizes update to match.

Question 5

Why did my file get bigger?

Accepted Answer

PDFs made mostly of text and vector drawings are often already compact. Ghostscript rewrites the whole file, so the result can come out slightly larger. Keep the original in that case.

Question 6

Can it open password-protected PDFs?

Accepted Answer

Yes. The tool asks for the password and unlocks the file on your device. The password is not saved or sent anywhere.

Question 7

Can I run it from a script or an AI assistant?

Accepted Answer

Yes. The freethetools npm package runs the same compressor on your computer, for scripts and AI assistants: npx -y freethetools run compress_pdf '{"file":"report.pdf"}'. Nothing is uploaded.

Runs	In your browser. Your files stay on your device.
Engine	Ghostscript 9.56, compiled to WebAssembly
First load	16 MB, then cached by your browser
Works offline	Yes, once the page has loaded
Licence	AGPL-3.0
Added	27 September 2026
Built by	Sapience Design
Source	tools/pdf/compress

Make a PDF smaller

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