Compress files for free.
Keep them private.
Reduce images, PDFs, audio, video and folders right on your device. No uploads, no accounts, no waiting for a server — your files stay exactly where they belong: with you.
Start compressing How privacy worksLocal processing
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Image · PDF · ZIP · Audio · Video
Choose a compressor
🖼️ Image Compressor
Shrink JPG, PNG, WebP and BMP photos for websites, email and social media. Control quality, resize dimensions and convert formats in a batch.
Compress images📄 PDF Compressor
Make PDFs easier to email and upload by re-rendering pages at a lighter resolution. Ideal for scans, handouts and image-heavy documents.
Compress a PDF🗜️ ZIP Compressor
Bundle any files into a single ZIP archive with adjustable DEFLATE compression. Perfect for sharing projects and backups.
Create a ZIP🎵 Audio Compressor
Convert MP3, WAV, OGG and M4A audio to compact MP3 at 64–192 kbps. Great for voice notes, podcasts and demos.
Compress audio🎬 Video Compressor
Reduce video size with resolution presets and a CRF quality slider, powered by FFmpeg running entirely in your browser.
Compress video📚 Guides & FAQ
Learn when to use JPEG, PNG or WebP, how to send smaller videos, and how to compress a PDF without wrecking readability.
Read the FAQHow compression actually works
Compression is a trade between three things: file size, quality, and the time it takes to encode and decode. Every compressor looks for patterns it can describe more efficiently. A clear blue sky in a photo, a repeated word in a document, or silence between spoken words all contain redundancy — information that can be represented with fewer bits.
Our tools run proven open-source encoders directly in your browser using technologies such as Canvas, Web Audio and WebAssembly. When you drop a file onto a tool page, your browser reads it into memory, re-encodes it with the settings you chose, and offers the result as a download. At no point is the file sent to FileCompressor.site or to any other server.
Lossy vs lossless — the one decision that matters most
Lossless: smaller, identical
Lossless compression removes redundancy without discarding any data. ZIP is the classic example: unzip the archive and you get the exact original bytes back. PNG also uses lossless compression. Choose lossless for archives, documents you must preserve exactly, screenshots with sharp text, and anything you will edit again.
Lossy: much smaller, slightly different
Lossy compression discards information your eyes or ears are least likely to miss. JPEG photos, MP3 audio and most video formats are lossy — they can be 5–20× smaller, but re-saving them repeatedly gradually degrades quality. Choose lossy for final delivery: web images, shared videos, streamed audio and email attachments.
A practical rule: keep one lossless master for editing, and export lossy copies for sharing. That gives you both quality insurance and small files where they count.
Why “client-side” is a real privacy advantage
Most online compressors upload your file to a remote server, process it there, and let you download the result. That means a copy of a contract, a family photo or an unreleased song briefly lives on someone else's computer. FileCompressor.site is different by design: the code is delivered to your browser once, then all of the work happens on your device. Close the tab and the in-memory copy is gone. You can even load a tool page, disconnect from the internet, and keep compressing.
We still use cookies — with your consent — for preferences and advertising, and we explain that plainly in our Privacy Policy. But cookies are not your files. Your files are never uploaded, never stored, and never seen by us.
Frequently asked questions — teasers
Is it really free?
Yes. The tools are free to use and supported by advertising that only loads after cookie consent.
Will compression hurt quality?
It depends on the format and settings. Our guides explain safe starting points for photos, PDFs and video.
Is there a file-size limit?
The limit is your device's memory and browser, not our server — because there is no server processing. Very large videos may be slow on older phones.