Audio & Media

Video Compressor — Reduce MP4 & MOV Size Online

Compress videos in your browser with FFmpeg. Choose presets for web sharing, adjust quality and resolution, and download a smaller MP4 or WebM — 100% client-side, no uploads.

MP4 & WebM OutputHigh Quality PresetQuality PresetsResize 1080p → 480pAudio ControlMobile OptimizedOutput Preview100% Client-Side

Private by design. Videos are processed with FFmpeg inside your browser. Files never leave your device — safe for personal, work, or confidential footage.

Works on mobile. Touch-friendly controls, mobile file limits, and faster encoding presets on phones and tablets. Keep the tab open while compressing.

Common use cases

📱

WhatsApp & Social

Shrink clips before sharing on messaging apps with size limits.

✉️

Email Attachments

Reduce MP4 size to fit common email attachment limits.

🌐

Website & CMS Uploads

Compress hero videos and demos for faster page loads.

🔒

Private Footage

Process sensitive recordings locally — nothing uploaded.

How it works

1
Upload
Drop or select MP4, MOV, WebM, or MKV (up to 150 MB on mobile, 500 MB on desktop).
2
Choose preset
Pick High Quality, Balanced, Web & Social, Smallest File, or custom CRF and resolution.
3
Download
FFmpeg re-encodes locally. Download your compressed MP4 or WebM when done.

Video Quality, CRF, and File Size

CRF, or Constant Rate Factor, tells the encoder how much visual detail to preserve. Lower CRF values retain more detail and usually create larger files; higher values trade more detail for a smaller result. Because motion and visual complexity vary, CRF does not promise an exact output size.

Selecting Original resolution preserves the source dimensions only. It does not preserve the original bitrate, codec, or file size because the video is still re-encoded. Choose High Quality for the least aggressive compression, or use Custom with a low CRF when visual quality matters more than maximum savings.

Output Format, Resolution, and Audio

Each setting affects compatibility, processing time, and file size. The best combination depends on how the video will be shared.

Setting	Best choice	Effect
MP4 / H.264	Phones, messaging, email, social media	Broadest playback compatibility
WebM / VP9	Modern browsers and web publishing	Efficient compression but slower encoding
Lower resolution	Small screens and strict upload limits	Often produces the largest size reduction
Remove audio	Muted demos, backgrounds, and loops	Removes the audio stream entirely

Browser Processing and Large Videos

Browser compression must keep the source video, WebAssembly encoder, working frames, and completed result in device memory. A file can fail even below the listed size limit when it has a long duration, high resolution, or the device has limited free memory. Close heavy tabs, keep this page open, and begin with MP4 plus a faster preset on mobile.

Technical reference: FFmpeg documentation ↗.

Why browser-based compression?

Cloud compressors upload your entire video to a remote server. This tool uses FFmpeg WebAssembly — the same engine as many desktop apps — running entirely on your device. It is slower than native software but keeps your footage private and works without an account.

Continue Your Audio and Video Workflow

Need a different video task? Use the Video Joiner to combine clips, or extract a soundtrack with Video to MP3. After extraction, refine the result with the Audio Cutter, change formats using the Audio Converter, or combine tracks with the Audio Joiner.

For the broader shift from broadcast channels to digital video and streaming, read Television: Then vs Now.

To learn about research that helped digital video and HDTV scale, read the Arun Netravali profile.

Frequently asked questions

Tip: For fastest results on mobile, use Smallest File or Web & Social presets and shorter clips under one minute when possible.

View all in this category →

Every tool in our media suite runs in your browser — no uploads, no sign-up. Compress video, convert audio, trim clips, join tracks, change speed, or boost volume.

Live