Compress MP4, MOV, AVI, MKV & WebM locally in your browser. No upload, account, or watermark.
One-click sharing presets: Compress for Discord / Compress for Gmail
Select a video to get started
TL;DR
Choose a maximum video size in MB or MiB. Localsquash uses local two-pass H.264 encoding, measured audio, and actual-byte checks to aim for 95-100% of your limit. Exact size is not guaranteed: smaller files are identified and oversized files are not reported as success. Fitting MP4 results download automatically. No upload, account, or watermark.
When an upload form has a file-size limit, choosing a quality setting alone is unpredictable. This tool uses the clip's duration, an audio budget, and two-pass H.264 encoding to aim near your requested size. FFmpeg runs in your browser through WebAssembly, without sending your footage to a server. The tool checks the actual exported bytes and complete selected clip duration before showing a result.
Choose a supported local file. The engine reads its metadata even when the browser cannot preview the original format. Your video stays on your device; nothing is uploaded.
Enter the destination's size limit and choose MB or MiB. Leave a little extra headroom if you do not know the destination's exact byte limit.
Optionally trim the video with the timeline handles. Auto resolution estimates suitable dimensions without upscaling. Audio is retained unless you explicitly remove it.
Wait for both passes and the size check. MP4 results that fit your limit download automatically. Review the verified size in the compression panel; use Download again if your browser blocks the download. Oversized results are clearly identified, not automatically downloaded.
Busy scenes need more bits than static slides to look equally clear. Two-pass encoding allocates the available bits across the clip, but cannot guarantee both a tiny file and unchanged quality. A file-size target is useful when the destination has a hard upload limit.
If you care more about visual quality than a hard size cap, use the quality-based video compressor with CRF, crop, and resolution controls instead.
The goal is 95-100% of the requested maximum. MP4 overhead and encoder behavior vary, particularly for very short or simple clips. Up to three encoding attempts adjust the budget. A below-range file is reported honestly; padding is never added to make it look exact.
The complete selected clip must survive the duration check. The tool does not truncate the output to force a smaller file. If it still exceeds the limit, increase the size, trim the source yourself, or reduce the audio budget. Oversized results require a manual download and are clearly marked as not meeting the limit.
Media files are not uploaded. The engine is downloaded on first use, and processing runs locally in the open tab. Reloading offline is not guaranteed. Files must be smaller than 2,000 MB, and available RAM can impose a much lower limit.
Keep the tab open while encoding; mobile browsers may suspend background jobs. Two-pass encoding takes longer than quality-based compression. For large, long, or HDR videos, a desktop encoder is a better fit. HDR tone mapping is not supported by this tool.
The output is H.264 MP4 with optional AAC audio. The first video and audio tracks are used; subtitles, chapters, and additional tracks are not copied. Actual input support depends on the codecs available in the bundled FFmpeg build, not just the filename.
Supported SDR footage can be re-encoded to fit your chosen size budget. Selecting a larger target does not restore detail already lost to compression.
Supported WebM recordings can be converted to H.264 MP4 for sharing. The selected clip duration and actual output size are checked after encoding.
A source may be convertible even when its browser preview is unavailable. Visual trimming needs a working preview, but full-video conversion can still work.
Use the destination's exact byte limit when you can. Leave headroom if its MB label is ambiguous; rounding a displayed size does not change the actual bytes.
Removing unwanted seconds gives the remaining footage a larger share of the same file-size budget. Use the timeline handles and reset button to choose the clip yourself.
A very small budget spread across a large frame can look worse than a lower-resolution version. Start with Auto, then choose a smaller resolution if the result is not clear enough.
Audio uses space that is unavailable to video. Lower its bitrate or explicitly remove it if appropriate. Surround audio is downmixed to stereo AAC.
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