Free Video Compressor

How this compressor is different

Upload-based compressors need the whole file on their server before they start, and many cap free files at 500 MB or 1 GB. This one sends nothing. Your browser decodes the video, and your device's own video encoder compresses it, the same hardware your phone or computer uses to record. There is no queue, no credits and nothing to sign in to.

Because the file stays on your machine, a meeting recording or a family video never passes through a third party. You can check this yourself: open your browser's network panel while a compression runs and look for a request carrying your video. There is none. Once the page has loaded, it also works with no network connection.

How to compress a video

Drop a video onto the page or click to choose one. In the settings panel, Target size is a bar you can drag left or right, with four buttons under it at 10%, 30%, 50% and 70%. The filled part of the bar is the share of the original size that remains. After a video is loaded, each button also shows the size it gives. Screen size lists Original with its resolution, then the lower steps (1080p down to 240p) that are below your source. Below that, the estimate row shows the original size, a ring with the percentage that remains, and the After size. Click the After size (the pencil icon) to type an exact size in MB.

Press Compress video. A progress window shows the percentage, elapsed and remaining time, and a Stop button. When it finishes, the Original, Compare and After tabs let you check the result before you press Download. If you close the page before downloading, the last result stays in your browser for up to 7 days. To cut the video shorter as well, use Trim Video ↗.

Advanced settings

Advanced, next to the Screen size heading, opens a row of three menus. Frame rate offers Original, 60 fps or 30 fps. At a fixed target size, 30 fps leaves more bits for each frame. Format offers MP4 (H.264), MP4 · HEVC, WebM (VP9) and WebM · AV1, but only the ones this browser can encode on this device. MP4 (H.264) is the default and plays in the most places.

Audio is kept as is by default. You can also re-encode it at 128 or 64 kbps, or remove it. Audio with more than two channels (5.1 and similar) is mixed down to stereo when re-encoded, and only the first audio track is kept.

When a size can only be reached at a lower resolution, the panel picks that resolution itself and marks the row with a dashed amber frame. It then shows "Resolution set to W × H to reach this size." If that is still not enough, it may lower the audio to 64 kbps and say so. When the estimate is 97% of the original or more, it shows "At this setting the file stays about the same size."

What compression does to a video

A video file's size is close to bitrate × duration. Bitrate is how many bits the encoder may spend per second. With fewer bits, it saves on detail in flat areas and fast motion first, and at very low bitrates you see blocks and smearing. Resolution and frame rate set how many pixels there are to describe each second, so a lower screen size leaves more bits per pixel.

For each resolution the compressor has a minimum bits-per-pixel. If your target size falls below it, the panel moves to the next lower screen size. The encoder writes a keyframe every two seconds, so the result seeks quickly in any player.

Formats and limits

Input: MP4, MOV, WebM, MKV, TS, M2TS and MTS. AVI, WMV, FLV and other older formats are not supported. Output is MP4 or WebM. The original file is never changed; the result is a new file, written to disk as it is produced, so files of several GB work.

HEVC (H.265) input can only be read on devices with a hardware HEVC decoder, because Chrome has no software HEVC decoder. On some Macs, Chrome stops decoding certain H.264 files partway through. The page then restarts with software decoding, replaces any frames that still cannot be decoded with the previous frame, and states how many were replaced. If the browser cannot decode the audio track partway through, compression restarts and keeps the original audio as is, with a note under the result.

Frequently asked questions