Compress Video Free Online
Make MP4, MOV, WebM, or MKV videos smaller for free in your browser. Re‑encodes to efficient VP9 + Opus WebM with no upload.
You usually compress video because the file is blocking something practical: it will not attach, uploads too slowly, makes a page heavy, takes too much storage, or forces someone to download a huge file just to review a simple clip.
Original exports are often built like master files: high bitrate, full resolution, and extra detail for editing. That is useful while you are working on the footage, but wasteful when the video only needs to be watched, shared, reviewed, or embedded.
A compressed WebM is the delivery version: smaller, faster, and easier to move. Keep the original for editing and archive. Send the compressed version when someone only needs to watch it.
Large videos create friction everywhere: a 4K phone clip can weigh hundreds of megabytes, an OBS recording can be too big for a bug report, a product demo can slow down a landing page, and a client preview can become a giant download instead of a quick review.
Compression reduces file size by using fewer bits where viewers are less likely to notice. Static slides, UI recordings, talking-head clips, tutorials, walkthroughs, and social drafts often shrink especially well because they do not need the same bitrate as the original export.
The trade-off is simple: smaller files lose some visual detail. The goal is not to beat the original. The goal is to create a version that is light enough for the job and still looks good where it will actually be watched.
GrepCut decodes your video in the browser and re-encodes it as VP9 video with Opus audio inside a WebM container. This format is built for modern web playback and can create much smaller delivery files than many default camera, phone, screen recorder, and editor exports.
The compressor does not use one fixed setting for every file. It adjusts the compression budget based on the source, duration, resolution, tracks, and selected profile.
Extreme mode is the most aggressive. It limits output height to 480p and uses a lower video and audio budget. Use it when the size limit matters more than perfect detail.
Because GrepCut re-encodes the file, compression takes longer than a simple format change. The upside is privacy: client footage, internal demos, private videos, and large recordings do not need to be uploaded to a third-party server just to make them smaller.
Sometimes a compressed video only gets a little smaller. In rare cases, it can even get larger. That usually happens when the source was already compressed efficiently, the selected quality target is still high, or the content is difficult to compress.
Grain, noise, fast motion, tiny text, gameplay, water, leaves, confetti, and constant scene changes all need more data to look clean. Bitrate is the main size lever, but duration matters too: the longer the video, the more total data it needs.
For the biggest real-world reduction, cut before you compress. Remove dead air, loading screens, countdowns, repeated takes, and unused endings first. A shorter video is the cleanest compression win.
How much smaller will my video get?
It depends on the source. High-bitrate phone clips, screen recordings, and editor exports can shrink a lot. Files that are already well-compressed may shrink only slightly. Use Extreme for the smallest output, Smaller file for a middle path, and Balanced when quality matters.
Is my video uploaded anywhere?
No. GrepCut compresses your video locally in the browser using WebCodecs and WebAssembly. Your file stays on your device.
Will compression reduce quality?
Yes. GrepCut re-encodes the video, so compression is lossy. The point is to trade some detail for a smaller file. Use Balanced when the video represents your work, and keep the original if you may need the best version later.
Why is my compressed video still large?
Some videos are harder to compress. Grain, noise, camera movement, gameplay, water, leaves, confetti, fast cuts, and tiny UI text all need more data to look clean. Try Extreme or trim the clip first if size matters most.
Why did my compressed video get bigger?
That can happen when the original was already encoded efficiently and the new settings use more bitrate than necessary. Compression works by reducing bitrate, lowering resolution, simplifying audio, or shortening the video - not by magic.
What formats can I compress?
GrepCut accepts MP4, MOV, WebM, and MKV inputs. The output is a VP9 + Opus WebM file optimized for modern browsers, web sharing, and smaller delivery files.
Should I use WebM or MP4?
Use WebM when small size and web delivery matter most. Use MP4 when broad compatibility matters more, especially for phone galleries, older TVs, some editors, or people opening the file outside a modern browser.
What is the fastest way to make a video smaller?
Cut first, then compress. Removing unused footage reduces duration before compression even starts. After that, choose Smaller file or Extreme if the file still needs to fit under a limit.