Max 500MB per file • Unlimited files • No signup required
✨ Compress videos by up to 90% with our free online tool
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Quality Control
Choose from Ultra HD to Maximum compression
speed
Fast Processing
WebAssembly-powered client-side compression
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Batch Download
Compress multiple videos and download as ZIP
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100% Private
Videos never leave your device
How to Compress Videos Online
1
Upload Your Videos
Drag and drop or browse to upload MP4, MOV, AVI, WebM, MKV, WMV, FLV, or M4V files.
2
Choose Quality Level
Select High Quality, Balanced, or Small Size preset—or fine-tune with the CRF slider.
3
Compress All
Click "Compress All" to process your videos. Watch real-time progress for each file.
4
Preview & Download
Preview compressed videos, download individually, or get all as a ZIP file.
Frequently Asked Questions
How do I compress a video for email attachment?expand_more
Upload your video and select "Small Size" or "Balanced" preset. Most email services limit attachments to 25MB. Our tool shows the output size in real-time so you can hit your target.
What formats does the compressor support?expand_more
All major formats: MP4, MOV, AVI, WebM, MKV, WMV, FLV, M4V. Output is always MP4 with H.264 encoding for universal compatibility across Slack, Discord, email, and web.
Is this tool safe for work videos?expand_more
Yes. All compression runs locally in your browser using WebAssembly. Videos never leave your device or touch external servers. No data is collected.
Can I compress videos for Slack or Microsoft Teams?expand_more
Absolutely. Slack allows up to 1GB with paid plans but compresses files aggressively. Pre-compressing to under 50MB with "Balanced" quality delivers better playback quality.
Why is my compressed video larger than the original?expand_more
Highly-compressed source videos (from phones or screen recorders) may not shrink further at "High Quality" settings. Try "Balanced" or "Small Size" for actual reduction.
How long does compression take?expand_more
Processing speed depends on your device. A 100MB video typically takes 30-60 seconds on modern laptops. Progress is shown in real-time.
How Video Compression Works: Codecs, Bitrate, and Quality
Video files are large because they contain 24–60 individual images (frames) per second of footage. A single frame of 1080p video contains over 2 million pixels, and at 30 frames per second, that is 60 million pixels every second. Without compression, one minute of 1080p video would consume approximately 10 GB of storage. Video codecs solve this by exploiting two types of redundancy: spatial (within a single frame) and temporal (between consecutive frames).
The H.264 codec (also called AVC) is the most widely compatible video codec, supported by virtually every device and platform manufactured since 2010. H.265 (HEVC) improves upon H.264 by achieving 25–50% better compression at the same visual quality, but hardware decoding support is less universal. The newer AV1 codec, developed by the Alliance for Open Media (Google, Mozilla, Netflix, Amazon), offers compression comparable to H.265 but is royalty-free. Our compressor uses H.264 for maximum compatibility.
The Constant Rate Factor (CRF) is the most important compression parameter. CRF values range from 0 (lossless) to 51 (worst quality). A CRF of 23 is considered visually lossless for most content — meaning the average viewer cannot distinguish the compressed video from the original in normal playback. Lowering the CRF by 6 roughly doubles the file size, while increasing it by 6 roughly halves it. Our tool defaults to CRF 28, which provides excellent quality with significant size reduction.
Resolution scaling is another powerful compression technique. A 4K video (3840×2160) contains four times as many pixels as 1080p (1920×1080). If your video will be viewed on phones or shared via messaging apps, downscaling from 4K to 1080p before compression can reduce file size by 70–80% with minimal perceived quality loss on mobile screens.
How to Compress Videos for Email, Social Media, and Web
1
Select your video file
Click to browse or drag your MP4, MOV, or WebM video file. The tool supports files up to several GB depending on your device's available memory.
2
Choose compression preset
Select from presets optimized for common use cases: "Email" (under 25 MB), "Social Media" (balanced quality and size), "Web" (optimized streaming), or "Custom" to set CRF and resolution manually.
3
Wait for encoding
FFmpeg runs entirely in your browser via WebAssembly. Processing time depends on video length and your device's CPU power — a 5-minute 1080p video typically takes 2–5 minutes to compress on modern hardware.
4
Preview and download
Review the compressed file size and play back the result to verify quality. If satisfied, download the compressed MP4 file directly to your device.
Key Features
FFmpeg in Your Browser
Uses the full FFmpeg multimedia framework compiled to WebAssembly. The same encoding engine used by YouTube, Netflix, and professional video editors.
CRF-Based Quality Control
Uses Constant Rate Factor encoding — the gold standard for quality-optimized compression. Allocates more bits to complex scenes and fewer to simple ones.
Resolution Scaling
Optionally downscale 4K to 1080p or 720p before compression for dramatically smaller files suitable for mobile viewing and messaging.
Complete Privacy
Your video never leaves your device. Processing happens on your CPU via WebAssembly — no cloud servers, no upload wait times, no third-party access.
Frequently Asked Questions
Why does video compression take longer than image compression?
Video files contain thousands of individual frames, and the encoder must analyze patterns between consecutive frames (temporal compression). A 5-minute 1080p video at 30fps contains 9,000 frames — each must be analyzed and encoded. WebAssembly runs at near-native speed, but encoding is inherently CPU-intensive.
How small can I compress a video for email?
Most email services limit attachments to 25 MB. A 5-minute 1080p video, typically 300–500 MB, can be compressed to under 25 MB by using a higher CRF (32–36) and downscaling to 720p. Quality will be noticeably reduced but perfectly watchable for casual sharing.
Will the compressed video play on all devices?
Yes. Our compressor outputs H.264 MP4 files, which is the most universally compatible video format. It plays natively on all modern phones, tablets, computers, smart TVs, and web browsers without requiring any additional codecs or players.
Can I compress a 4K video in my browser?
Yes, but it requires significant RAM (4–8 GB of available browser memory for long 4K videos). Modern laptops and desktops handle this well. On phones or older devices, we recommend downscaling to 1080p first. The tool will warn you if memory is insufficient.
What is the difference between bitrate and CRF encoding?
Bitrate encoding (CBR/VBR) targets a specific file size but quality varies — simple scenes get too many bits while complex scenes get too few. CRF encoding targets consistent visual quality throughout, allocating bits dynamically. CRF produces better quality per byte and is the industry standard for single-pass encoding.
