Does MKV to MP4 reduce quality?

The video is re-encoded to H.264. On the High setting the difference is not visible on a phone or laptop screen.

Will HEVC or VP9 MKV files work?

Yes. Any codec FFmpeg can decode is converted to H.264. HEVC and VP9 sources take longer to decode.

Is there a file size limit?

Browsers handle roughly 1 GB in memory. Files under about 300 MB and 1080p are comfortable; 4K works but is slow.

Is it free and private?

Yes. No sign-up, no watermark, and the file never leaves your device.

Free · No sign-up

MKV to MP4

Convert a Matroska MKV into an MP4 your phone, TV and editor will open – no upload, no sign-up, no watermark added.

AI · Paid creditsAI Video Watermark Remover AI Video Eraser

No upload
No sign-up
No new watermark
MP4, MOV, WebM, MKV, AVI

Drop a video here or click to choose

MP4, MOV, WebM, MKV, AVI · best under 300 MB

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A real input to try

Start with an openly licensed sample.

An 8-second blue-mug clip from the Apache-2.0 remove-ai-watermarks project, documented as Google Flow / Veo 3.1 Fast. This MKV is a local remux of the source MP4 with identical H.264/AAC packets. It is a conversion input, not a provider-native format export or this tool’s result. Browser container support varies.

Input · video/x-matroska

This card shows an input, not a processed result. Loading it does not upload it or start a paid task.

Source: wiltodelta · Apache-2.0
Input: 1280 × 720 · 0.89 MiB

Attribution and modifications · Media facts and hashes

MKV is a flexible container that can hold almost any codec, several audio tracks and subtitle streams. That flexibility is why phones, smart TVs, iMovie and many websites refuse it. MP4 is the format they all agree on.

This converter re-encodes the MKV to an MP4 with H.264 video and AAC audio. The first video and audio track are used. Drop the file in, click Convert, download.

The whole job runs in your browser with FFmpeg WebAssembly. Nothing is sent to a server, no account is needed, and no watermark is added.

Subtitles are not carried over

Soft subtitle tracks inside the MKV are dropped. Download the .srt separately if you need it.

Only the first audio track

If the MKV has several languages, the first track is used. Check which one that is before converting.

Large MKV files

Full-length recordings are often over 1 GB, which is more than a browser can hold. Cut a shorter section with the video cutter first.

All tools

A place for every edit.

Remove a logo, refine your footage, change a format or take the sound with you. Find the tool for your next step.

15 tools

Watermark removal

Start with the part you want to remove.

10 tools

Edit video

Shape the frame, timing and movement.

7 tools

Convert

Get the format your next step needs.

3 tools

Audio

Keep the sound, without the video.