Video Converter
Convert between MP4, WEBM, AVI, MOV, and MKV formats. 100% client-side.
Loading Video Converter...
Please wait while we load the conversion engine (~30MB)
Explore Related Media Tools
The Secure Way to Convert Videos
Video Converter is a professional-grade tool designed for privacy and speed. Unlike other converters that require you to upload your files to slow, insecure servers, our tool processes everything directly in your browser. Switch formats, resize for social media, or compress files for email—all without your data ever leaving your device.
Private & Secure
Zero server uploads. Your personal videos are processed locally using WebAssembly, ensuring 100% data privacy.
Resize & Compress
Smart resizing options. Downscale 4K footage to 1080p or 720p to save huge amounts of storage space.
Audio Control
Remove audio tracks with a single click. Perfect for creating silent background videos or stock footage.
Quality Control
Choose between High, Medium, or Low quality presets to find the perfect balance between visual fidelity and file size.
Mobile Ready
Fully responsive design works on phones and tablets. Convert videos on-the-go without installing any apps.
Instant Preview
Watch your input video and preview the converted result instantly with our built-in video player.
Understanding Video Formats
MP4 (MPEG-4 Part 14)
The "Universal Language" of video. MP4 files work on iPhones, Androids, Windows, Macs, Smart TVs, and Game Consoles. It typically uses the H.264 video codec and AAC audio codec, offering high quality with small file sizes.
Best For: YouTube uploads, Social Media sharing, WhatsApp, and general storage.
WEBM (Web Media)
An open media format developed by Google specifically for the web. It uses the efficient VP8 or VP9 codecs. While slightly less compatible with older devices than MP4, it powers most videos you see on modern websites.
Best For: Website backgrounds, HTML5 video players, and high-efficiency streaming.
MOV (QuickTime)
Apple's proprietary container format. High quality and often easier to edit in software like Final Cut Pro or Adobe Premiere. If you record video on an iPhone, it likely starts as a MOV file.
Best For: Editing on Mac, High-quality archiving, Apple Ecosystem.
MKV (Matroska)
A robust, future-proof container that can hold unlimited video, audio, picture, or subtitle tracks in one file. It's famous for causing "File not supported" errors on TVs but is beloved by archivists for its flexibility.
Best For: Movie archiving, preserving subtitles, multi-language videos.
Common Conversion Mistakes
- Confusing "Container" with "Codec"
MP4 is just a box (container). The video inside (codec) matters more. Our converter ensures standard H.264 compatibility inside MP4s so they play everywhere.
- Expecting Higher Quality from Upscaling
Converting a 480p video to 1080p won't make it look better—it just makes the file larger and blurry. Always convert down (1080p → 720p) or stay same.
- Processing 4K Videos in Browser
4K files are massive. Since we use your browser's resources, converting a 5GB 4K file might crash your tab. Stick to files under 500MB for best stability.
Pro Tips for Best Results
- Use "Medium" Quality for Email
Email attachments often have a 25MB limit. Use the "Medium" quality preset and 720p resolution to easily shrink a 100MB video down to ~20MB.
- Mute Audio to save ~15%
If you're making a background video or a GIF-like loop, removing the audio track can significantly reduce file size without touching video quality.
- Check the Preview First
Always play the first few seconds of your result in our built-in player before downloading to ensure the audio is synced and quality is acceptable.
Frequently Asked Questions
Is it safe to convert private/confidential videos?
Yes, it is 100% safe. Unlike other converters that upload your video to a cloud server, our tool processes your file directly in your browser using WebAssembly technology. Your video data never leaves your device, making it perfect for personal, legal, or confidential footage.
What is the best format for YouTube or Instagram?
MP4 (H.264 video + AAC audio) is the universal gold standard for social media. It offers the best balance of quality and file size and is compatible with YouTube, Instagram, TikTok, Facebook, and Twitter. Select 'MP4' and 'High' quality for the best results.
How can I reduce the file size of my video?
You have three options: 1) Change the Resolution (e.g., 1080p to 720p) which dramatically lowers size. 2) Lower the Quality setting (Medium or Low), which increases compression. 3) Mute the audio if sound isn't needed. Combining these can reduce file size by up to 80%.
Why won't my converted video play on my iPhone?
iPhones (iOS) are picky about formats. They natively support MP4 and MOV (QuickTime) with H.264 or HEVC codecs. They often struggle with MKV or WEBM files unless you use a third-party player like VLC. For maximum compatibility with Apple devices, always choose MP4 or MOV.
Does converting video lose quality?
Generally, yes. Most video formats (MP4, WEBM) are 'lossy', meaning they throw away some invisible data to save space. Each time you convert, a tiny bit of quality is lost. To minimize this, use our 'High' quality setting, which uses a lower Constant Rate Factor (CRF) to preserve details.
Can I extract audio (MP3) from a video file?
This specific tool is designed for video-to-video conversion. However, if you simply want to remove sound, use the 'Mute Audio' checkbox. To extract MP3s, we recommend checking our dedicated Audio Converter tool (coming soon to the homepage) which handles extraction specifically.
Why is the conversion taking a long time?
Video conversion is a CPU-intensive task. Since we process files locally on your device (to ensure privacy), the speed depends entirely on your computer's processor. Higher resolutions (4K/1080p) and higher quality settings take longer to encode. Closing other browser tabs can help speed it up.
What is the difference between MP4 and MKV?
MP4 is the most compatible format, working on virtually every device. MKV (Matroska) is a more modern, flexible container that supports unlimited audio/subtitle tracks and higher quality streams, but it's less compatible with mobile devices and smart TVs. Use MKV for archiving, MP4 for sharing.
What is WEBM format used for?
WEBM is an open media format designed for the web. It uses the efficient VP8/VP9 codecs. It's often smaller than MP4 and is perfect for embedding videos on websites (like background videos) because it loads quickly and is royalty-free.
Can I use this tool offline?
Yes! Once the page and the conversion engine (~30MB) have loaded, you can disconnect your internet and continue converting videos. This is a great way to verify that no data is being sent to the cloud.
What does the 'Quality' setting actually do?
It adjusts the 'Constant Rate Factor' (CRF) of the encoder. 'High' Quality uses a low CRF (keeping more data/detail). 'Low' Quality uses a high CRF (allowing more data loss for smaller size). 'Medium' is a balanced default recommended for most users.
Is there a file size limit?
There is no hardcoded limit, but browser memory (RAM) is a constraint. For smooth performance within a browser tab, we recommend files under 200MB-500MB. Files larger than 1GB may cause the browser to crash due to memory exhaustion.