NEW · FFmpeg.wasm · 100% Browser-Based

Free Video Compressor

Shrink video files with platform presets — WhatsApp 16MB, Discord 10MB, Gmail 25MB, IG Reels 4GB, TikTok 500MB, YT Shorts. Runs in your browser. No upload, no signup, no watermark.

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Drop a video file
MP4 · MOV · WebM · MKV · AVI · GIF
Files stay on your device · Never uploaded

Why Do This in Your Browser?

Most online video compressors push your files to a server, run FFmpeg on the back end, and send the compressed result back. That works, but it means every clip — including private recordings, client work, and embargoed material — leaves your device. For platform-specific compression where the only goal is hitting a file-size cap, there's no good reason for the upload step.

This tool runs FFmpeg.wasm — the WebAssembly build of FFmpeg — entirely in your browser. The compression engine downloads once (~32MB), caches locally, and runs every job thereafter on your CPU. Files stay on the device. The platform presets calculate target bitrate from your video's duration and your chosen cap, then re-encode using H.264 (the codec every messaging app, social network, and email client decodes natively).

How It Works

Pick a preset that matches where the video is going. WhatsApp's hard cap is 16MB on most regions; Discord free tier is 10MB; Gmail attaches up to 25MB; Twitter/X allows 512MB; TikTok caps uploads at 500MB; YouTube Shorts and Instagram Reels both permit up to 4GB for short clips. The tool reads your video's duration and works backward: target_bitrate = (target_size_in_bits / duration_in_seconds) − audio_bitrate.

Output is H.264 + AAC in an MP4 container — the universally-compatible combination. For very small targets (1MB Discord posts, for example), you may need to also reduce resolution or framerate; the controls below let you do both. Original audio is preserved unless you explicitly mute it.

Tip: If your source is in MOV, MKV, or AVI, run it through the Video Converter first — H.264 in MP4 compresses faster and more predictably than less common codecs. Compress only the part you actually need by trimming the video first.

Common Use Cases

WhatsApp Sharing
Drop a phone-shot clip in, pick WhatsApp 16MB, get back something that sends in one tap.
Discord Posts
Free tier 10MB or Nitro 500MB — both presets included. No more 'file too large' errors mid-conversation.
Gmail Attachments
The 25MB Gmail cap is the single most common reason people open video compressors. One click, done.
Cold Email & Outreach
Sending a screen recording to a prospect? 10–25MB lands; 500MB+ gets quarantined.
TikTok & Reels Pre-Upload
Trim file size before upload to speed up posting on slow connections.
Storage Cleanup
Compress old phone videos to 30% of original size before archiving.

How We Compare

Honest read on free, paid, and self-hosted options for this kind of job:

UDT Video Compressor (this tool): Free, browser-based, runs FFmpeg.wasm locally. No file size cap, no upload, no watermark, no signup. Limitation: first compression downloads ~32MB of WebAssembly; large 4K+ files take longer than a desktop FFmpeg install.
Clideo: Free tier compresses but slaps a watermark on the output. $9/mo to remove. Cloud-based — your video goes to their servers.
Kapwing: Free tier limits to 4 minutes and adds a watermark. $16/mo to remove both. Cloud-based; great UI but the privacy story is the same as every other SaaS.
FreeConvert: Free tier capped at 1GB upload + queue waits. $9/mo paid plans. Cloud.
VEED.io: Free tier watermarks output and caps at 720p. $12–$30/mo. Cloud.
HandBrake (desktop): Free, open-source, runs locally — gold standard for batch compression. Requires download + install + learning curve. This browser tool gets you 90% of HandBrake for a 30-second compression job.

Frequently Asked Questions

Is this video compressor really free?
Yes — completely free, no watermark, no time limits, no file size caps, no signup. The site is supported by ads elsewhere; the tools themselves are unrestricted.
Are my videos uploaded anywhere?
No. The entire compression runs in your browser using FFmpeg.wasm (LGPL-licensed open source). The WebAssembly binary downloads once (~32MB) and caches locally. After that, the tool works fully offline. Your video never touches a server.
Why does the first compression download 32MB?
FFmpeg.wasm is the WebAssembly build of FFmpeg — the same engine used by virtually every desktop video tool. It downloads once to your browser cache, then runs every subsequent job locally without re-downloading.
What's the maximum file size?
There's no hard limit imposed by this tool — your browser's memory is the practical ceiling. Most modern laptops handle 1–2GB videos comfortably; phones cap around 500MB. For 4K+ files over 2GB, a desktop FFmpeg install will be faster.
Does it work for WhatsApp's 16MB cap?
Yes — the WhatsApp preset is calibrated to land at 15.5MB to give a small safety margin against WhatsApp's exact-byte counter. A 3-minute 1080p clip typically compresses cleanly to under 16MB with no visible quality loss.
Will it add a watermark?
No. The output is clean MP4 (H.264 video + AAC audio). The free tools that add watermarks are doing so as upsell pressure to their paid plans.
Why is the file size sometimes a little under or over the target?
Bitrate-based compression isn't byte-exact — final size depends on how compressible the content is (a video of a static slide compresses smaller than a fast-action montage at the same bitrate). The presets include a ~3% safety margin to stay under the cap.
Can I compress without losing quality?
True 'lossless' compression of an already-compressed source video is impossible — you can only re-encode at lower or equal quality. For visually-lossless results, keep CRF below 23 (the tool uses CRF when you pick 'Custom Quality' instead of a size target).

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