Compress video
Make an MP4, MOV or WebM smaller for sharing, uploading or emailing. The video is re-encoded by ffmpeg running inside this tab, so it never leaves your device.
Drop a video to squeeze
MP4, MOV, WebM, MKV or AVI, up to 800 MB. Encoded on your device; nothing is uploaded.
How to reduce video size
- Drop the video. We read its length and resolution in the browser.
- Pick a quality level, or switch to "A file size" and type the limit you need to meet.
- Lower the resolution if the source is 1080p or 4K and you're sharing to phones; 720p is the sweet spot.
- Press Compress video. Keep the tab open until it finishes, then download the MP4.
Three levers, and what each costs
| Lever | Effect on size | What you give up |
|---|---|---|
| Bitrate / CRF | Directly proportional: half the bitrate, half the file | Blockiness in motion and dark scenes when too low |
| Resolution | 1080pā720p has 56% fewer pixels, so the same quality needs far fewer bits | Fine detail on big screens |
| Frame rate | 60ā30 fps saves a meaningful share, though less than half | Smoothness in fast action and gaming footage |
Not sure how many kilobits a target size leaves you? The video bitrate calculator does the arithmetic and warns when a resolution is too ambitious. The full reasoning is in how to compress a video.
Limits
Files up to 800 MB. Very long or 4K clips may run out of browser memory, especially on phones; trim them first. HDR footage is converted to standard dynamic range. Compressing is lossy: keep your original.
Questions people ask
Can I compress a video online for free without uploading it?
Yes. This page loads ffmpeg compiled to WebAssembly and runs it inside your browser tab. The video is read from your disk, encoded on your CPU and saved back as a download. We never receive it.
Which formats are supported?
Input: MP4, MOV (including iPhone HEVC in most cases), WebM, MKV, AVI and M4V. Output is always H.264 video with AAC audio in an MP4, which plays on practically every phone, browser, TV and social platform.
Why is it slower than desktop software?
Browser WebAssembly can't use your GPU's video encoder and runs on a single CPU thread here, while desktop apps like HandBrake use every core. Expect roughly real-time speed or slower on a laptop. For hours of footage, desktop software is the better tool.
What is CRF?
Constant Rate Factor is x264's quality dial: lower numbers mean higher quality and bigger files. 23 is x264's default, and each +6 roughly halves the bitrate. We offer 23, 27 and 31.
Should I pick a quality level or a file size?
Pick a file size when something enforces a limit (Discord, email, a form). Pick a quality level otherwise: it spends bits where the video needs them and usually looks better for its size.