How to use
01
Add your video
Drag a video in or browse for one. MP4, MOV, WebM, MKV, AVI and more are supported. Nothing is uploaded — the file stays on your device.
02
Dial in the settings
Choose an output format, then control quality with the CRF slider or a target file size. Optionally resize, crop to an aspect ratio, change frame rate, trim, or mute the audio.
03
Compress and download
Hit Compress. The first run downloads the ~30 MB engine, then everything happens locally. Preview the result, see how much smaller it is, and download.
Why Video Compressor
- 100% in-browser via FFmpeg.wasm — your video never leaves your device.
- Full quality control: CRF slider with High / Balanced / Small presets.
- Target file size mode: enter the MB you need and it picks the bitrate.
- Resize, crop to any aspect ratio, change frame rate, trim, and mute.
- Export MP4 (H.264) for compatibility or WebM (VP9) for smaller files.
- Free, unlimited, no watermark, no sign-up.
Common questions
Is my video uploaded anywhere?
No. Compression runs entirely in your browser using FFmpeg compiled to WebAssembly. The video is read locally and never sent to a server, which is why it works offline after the engine loads.
Why is the first compression slow to start?
On the first run the tool downloads the ~30 MB FFmpeg engine. After that it's cached, so subsequent runs start instantly. Compression itself runs on your CPU, so larger or longer videos take longer than a server would.
What's the difference between CRF and target size?
CRF (Constant Rate Factor) keeps a consistent visual quality and lets the file size fall where it may — lower CRF means better quality and a bigger file. Target size mode does the opposite: you set the MB you need and it calculates the bitrate to hit it, which is ideal for email or upload limits.
MP4 or WebM?
MP4 with H.264 plays virtually everywhere (phones, editors, social platforms). WebM with VP9 usually produces a noticeably smaller file at the same quality and is great for the web, but has slightly less universal support.
Is there a file size limit?
There's no hard limit, but because it runs in your browser's memory, very large files (multi-GB or long 4K clips) can hit memory limits. If a big file fails, trim it, lower the resolution, or compress in sections.
Is Video Compressor free to use?
Yes. Video Compressor is completely free. There is no sign up, no trial, and no usage cap.
Do I need an account to use Video Compressor?
No. You can start using Video Compressor straight away. We do not ask for an email address or a login.
Is my data uploaded to a server when I use Video Compressor?
No. Video Compressor runs entirely inside your browser, so the input you enter never leaves your device and nothing is sent to us.
Do you store the input I use with Video Compressor?
No. Because everything happens locally in your browser, there is nothing for us to store. Close the tab and it is gone.
How do I use Video Compressor?
Enter or paste your input and Video Compressor updates the result as you go. When it looks right, copy or download it with one click.
Does Video Compressor work on phones and tablets?
Yes. Video Compressor is responsive and works in any modern browser on mobile, tablet, and desktop.
Which browsers does Video Compressor support?
It works in current versions of Chrome, Firefox, Safari, and Edge. For the best experience, keep your browser up to date.
Is there a limit on how often I can use Video Compressor?
No. You can use Video Compressor as many times as you need, at no cost.
Can I use Video Compressor for commercial or client work?
Yes. You are free to use the output in personal, educational, and commercial projects.
Why is Video Compressor free?
The site is supported by advertising, which lets us keep every tool free and open to everyone.
What should I do if Video Compressor gives an unexpected result?
First check that your input is formatted as expected. If something still looks wrong, use the feedback link on the page and we will take a look.