MKV to MP4 Converter | Free Lossless HD

How to Convert MKV to MP4 Online

Complete video format conversion in three steps with our free MKV to MP4 tool

Upload MKV File

Click the upload button to select an MKV file, or drag and drop the file directly into the upload area

Select Conversion Mode

Choose lossless remux (fast) or re-encode mode (better compatibility)

Start Conversion

Click the start conversion button and wait for it to finish, then download the MP4 file

Download MP4

After conversion, click the download button to save the converted MP4 video file

What are MKV and MP4 Formats?

MKV and MP4 are both common video container formats. Understanding their differences helps you choose the right conversion method.

About MKV Format

MKV (Matroska Video) is an open-source, free multimedia container format that can hold an unlimited number of video, audio, subtitle, or image tracks in a single file. It is highly flexible and extensible, supports multiple encoding formats, and is commonly used for storing HD movies and video resources.

About MP4 Format

MP4 (MPEG-4 Part 14) is a widely used digital multimedia container format and one of the most compatible video formats available today. Almost all devices and platforms natively support MP4 format, including smartphones, tablets, smart TVs, game consoles, and more.

Why Convert MKV to MP4?

Device Compatibility: MP4 format is supported by virtually all devices and players, while MKV may not play on certain devices
Streaming Support: MP4 format is better suited for online streaming and supports progressive download
Editing Software Support: Most video editing software has better support for MP4 format
File Size: At the same quality level, MP4 files are typically smaller

Lossless Remux vs Re-encoding

Our MKV to MP4 tool offers two conversion modes. You can choose the right mode based on your needs.

Lossless Remux Mode

Lossless remuxing only changes the container format of the video without altering the video and audio encoding. This method is extremely fast, usually taking only a few seconds, and completely preserves the original video and audio quality.

Advantages: Fast conversion, lossless video quality, lossless audio quality

Disadvantages: If the original video codec is not supported by the MP4 container, compatibility issues may arise

Re-encode Mode

Re-encoding converts video and audio to MP4-compatible formats. This method is slower but ensures the output MP4 file will play correctly on all devices.

Advantages: Good compatibility, adjustable file size, supports more encoding options

Disadvantages: Slower conversion, may have slight quality loss

Common Use Cases for MKV to MP4 Conversion

Mobile Playback: Convert downloaded MKV movies to MP4 format for smooth playback on mobile phones
TV Playback: Smart TVs typically have better support for MP4 format
Video Editing: Convert MKV source material to MP4 format compatible with editing software
Online Sharing: MP4 format is better suited for uploading to video sites or social platforms
Space Saving: Compress video file size through re-encoding

Key Features of the MKV to MP4 Tool

Professional online video format converter supporting multiple conversion modes and HD video processing

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Lightning Fast

In lossless remux mode, conversion is extremely fast — even large files complete in seconds.

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Secure & Private

All conversion happens locally in your browser. Files are never uploaded to servers, protecting your privacy.

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HD Quality

Supports 4K, 1080P, and other HD video conversions. Lossless mode preserves original quality.

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Cross-Platform

Works on Windows, Mac, Linux, iOS, Android, and all platforms — no software installation needed.

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Multi-Track Support

Preserves multiple audio tracks and subtitles from MKV files — all still available after conversion.

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Completely Free

All features are completely free to use. No file size limits, no conversion limits.

FAQ

Frequently asked questions about the MKV to MP4 online tool

Will the converted video lose quality? +

When using lossless remux mode, video and audio quality are completely preserved because only the container format changes. When using re-encode mode, there may be slight quality loss, but we strive to maintain high-quality output.

What file sizes are supported? Are there any limits? +

In theory, any file size is supported, depending on your browser and device performance. We recommend files under 2GB for the best experience. There are no limits on the number of conversions — you can use it unlimited times for free.

Will my files be uploaded to a server? +

No. All conversion processes run locally in your browser. File data is never uploaded to any server. Your video files are processed entirely on your computer, protecting your privacy and security.

What's the difference between lossless remux and re-encoding? +

Lossless remux only changes the video container format without altering the codec — it's fast with no quality loss but may have slightly lower compatibility. Re-encoding re-encodes the video — it's slower but offers better compatibility and adjustable file size.

Why can't the converted video play on some devices? +

If you used lossless remux mode and the original video's codec is not supported by the target device, playback may fail. We recommend re-converting using re-encode mode to ensure compatibility.

What can I do if conversion is slow? +

Conversion speed depends on your computer performance and file size. If it's too slow, try: 1) Using lossless remux mode; 2) Closing other resource-intensive programs; 3) Ensuring your browser is up to date.

Is batch conversion supported? +

The current version supports single file conversion. Batch conversion functionality is under development — stay tuned. You can follow our changelog for the latest feature updates.

MKV to MP4 Online Converter