Free Online MKV Converter
This free MKV converter turns Matroska files into MP4, MOV, WebM, GIF, or plain audio, online, with no sign-up and no watermark. Upload any MKV, pick an output format (and, under Advanced, a video and audio codec such as H.264, H.265, AV1 or VP9), and EchoWave's cloud render farm handles the encoding, so a ten-year-old laptop converts as fast as a new workstation. Trimming, captions and color fixes live in the full editor. Nothing to install.
Free Online MKV Converter Features
EchoWave's MKV converter is used by streamers, video editors, and archivists around the world.
MKV, handled
Convert MKV files without installing anything
MKV is the container of screen recordings, disc backups, and long captures, and half the internet cannot play it. An MKV converter fixes that. EchoWave takes any Matroska file, re-encodes it on cloud servers, and hands back MP4, MOV, WebM, GIF, or plain audio. It sits inside the wider video converter library, next to the MP4 converter hub and pair pages like MKV to MP4.
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20
video formats accepted, MKV included
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6
output codecs, from H.264 to ProRes
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21
output formats, video and audio
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176
convert pairs across the site
Format toolkit
Everything between upload and download
A free converter for the format swap, and a full editor one click away for everything else.
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An MKV converter with real codec control
Convert MKV to MP4, MOV, or WebM, or keep the Matroska container and only swap the codec. H.264 plays everywhere, H.265 and AV1 shrink the file, and ProRes or DNxHR feed professional edit suites. The most common route is MKV to MP4, and MKV to MOV covers Apple workflows.
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Full quality, even when your browser cannot play MKV
Browsers cannot decode many MKV codecs, but the converter does not rely on them. Your upload arrives intact and the conversion runs through ffmpeg on EchoWave's servers at full quality.
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Shrink the file while you convert
Switching a big H.264 recording to H.265 typically lands the file at around half the size at similar quality. The converter has no bitrate or resolution controls, so for size-first jobs use the dedicated compress MKV tool.
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Cut before you convert
No point encoding three hours of capture to keep four minutes. The converter does not trim, so cut in the full editor first, then convert only what survives the cut. The cut MKV page covers cutting in depth, and the general video trimmer works on any format.
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Captions in the full editor
Auto speech-to-text transcribes the MKV, and 176 caption presets style the result, including word-by-word karaoke looks. Subtitles can be translated into 86 languages with Pro and burned into the converted file, so the MP4 you download is ready to post.
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Pull the audio out of an MKV
Save the audio track on its own with MKV to MP3 or MKV to WAV for podcasts, transcription, or archiving. The converter outputs audio formats such as MP3, WAV, FLAC, M4A, AAC and AIFF for free.
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MKV to GIF for clips and reactions
Turn a recording into a looping GIF by choosing GIF as the output format. MKV to GIF has the full walkthrough. For anything longer than a short clip, an MP4 is the better format anyway.
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Convert into MKV too
The trip works in reverse when you want Matroska's flexibility for archiving. MP4 to MKV, MOV to MKV, TS to MKV, and AVI to MKV all run through the same cloud pipeline, with H.265, AV1, ProRes, and DNxHR available inside the MKV container.
How it works
How to convert MKV files online
Four steps from Matroska file to a format that plays anywhere.
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Upload your MKV
Drag the file into the converter from any browser on Mac, Windows, Linux, or a Chromebook. EchoWave accepts 20 video formats, so mixed folders of MKV, TS, and WMV all go in the same door. Some MKVs will not preview in the browser, which is normal and does not affect the result.
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Pick the output format and codec
Choose MP4 for maximum compatibility, MOV, WebM or GIF for other uses, or audio-only MP3 and WAV. Open Advanced if you want to choose the video and audio codec, such as H.264, H.265 or AV1. The converter has no resolution, bitrate or frame rate options.
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Trim or caption first (optional)
The converter only changes the format. To cut dead air, add auto captions, fix brightness and contrast, or drop a logo in the corner, use the full editor first. Skip this step if you only need the format changed.
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Render in the cloud and download
Hit convert and the render farm does the encoding server-side, leaving your machine free. The result downloads with no watermark, no badge and no end card.
Where MKV shows up
What people convert MKV files for
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Publish OBS recordings
Screen recorders like OBS favor MKV because a crash mid-recording does not corrupt the file. Convert the capture to H.264 MP4 and it uploads cleanly everywhere.
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Play on phones and TVs
iPhones will not open MKV and plenty of smart TVs reject it. One pass to MP4 makes the same video play on every device in the house.
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Feed Premiere and other editors
Premiere Pro has no MKV import at all. Convert to MP4 for a quick edit, or to MOV with ProRes when the project needs a mezzanine file that scrubs smoothly.
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Shrink a bloated archive
Re-encoding old H.264 recordings to H.265 or AV1 reclaims serious disk space at similar quality. Keep the MKV container or move to MP4 while you are at it.
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Clip moments for chat
Grab ten seconds from a gaming session as a GIF or short MP4 for Discord and group chats. Trim on the timeline first so the loop starts exactly on the punchline.
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Save the audio track
Convert an interview or panel recording to MP3 or WAV for a podcast feed or a transcription pass. The video stays untouched in your original file.
Compare
How EchoWave compares
| Feature | EchoWave | CloudConvert | VEED | HandBrake |
|---|---|---|---|---|
| Accepts MKV uploads | Yes | Yes | Yes | Yes |
| Works in the browser, no install | Yes | Yes | Yes | No |
| Convert MKV to MP4, MOV and WebM | Yes | Yes | yes (MP4) | no MOV |
| H.265 and AV1 encoding | Yes | Yes | No | Yes |
| Custom bitrate and frame rate | codec only | Yes | limited | Yes |
| Trim and edit before converting | yes (full editor) | No | Yes | crop only |
| Auto captions with styled presets | yes (full editor, 176 presets) | No | yes (paid) | No |
| MKV to GIF | Yes | Yes | Yes | No |
| Watermark-free free exports | yes (no watermark) | Yes | No | Yes |
| Batch convert many files at once | No | Yes | No | yes (queue) |
| Works offline | No | No | No | Yes |
| Also a full video editor | Yes | No | Yes | No |
Based on each tool's public pages as of July 2026. Free tiers, format lists, and prices change, so check current pages before you commit.
Convert your first MKV in a couple of minutes
Upload an MKV, pick MP4, MOV, WebM, GIF, or audio, and let the cloud handle the encoding. The converter is free with no sign-up and no watermark; trimming, captions and higher resolutions are in the full editor.
What people are saying about EchoWave
About the EchoWave team
EchoWave is a browser-based video and audio editor built by Lemon Vault LLC since 2018. The people who build the editor write these guides and test every step in the production app before publishing.
Free Online MKV Converter FAQ
Is there a genuinely free MKV converter that works in the browser?
Yes. EchoWave's MKV converter is free, needs no sign-up, and adds no watermark, badge or end card. Upload an MKV, pick MP4 or another format, and download the result. Trimming, captions and paid export settings (1080p on Creator, 4K on Pro, 8K and 120 fps on Ultra) live in the full editor, where free exports are 720p MP4 with a small badge. There is nothing to install.
How do I convert MKV to MP4 without losing quality?
If the MKV already holds H.264 video with AAC audio, a desktop remux with ffmpeg or MKVToolNix is technically lossless because nothing gets re-encoded. EchoWave re-encodes instead, which is what lets you change the codec in the same pass. Resolution and bitrate are not adjustable in the converter, and your original upload is never modified, so you can run it again with different settings.
Why will an MKV file not play on my iPhone or TV?
MKV is a container, and Apple devices plus many smart TVs simply never added support for it, regardless of what codec sits inside. The video data is usually fine. Repackaging it as MP4 with H.264 fixes playback on essentially every device made in the last decade.
Why can I not preview my MKV in the browser before converting?
Browsers only decode a handful of codecs, and many MKV files use ones the browser cannot read, so a preview may be limited for those files. The conversion itself runs through ffmpeg on EchoWave's servers, which reads the file fully and renders at full quality. Limited preview never means a degraded output.
Which is better, MKV or MP4?
MKV is the more flexible container: it holds nearly any codec plus chapters, multiple audio tracks, and subtitle tracks, which is why archivists and screen recorders like it. MP4 is the more compatible one, accepted by phones, TVs, editors, and every social platform. Quality is identical for the same codec and bitrate, because the container is only the box the video ships in.
What happens to the subtitles inside my MKV?
Embedded subtitle tracks are not carried into the converted file. If you need them, export the track as an SRT first (MKVToolNix does this in seconds), then import the SRT into the full editor and burn the captions into the video. Or skip the extraction and let auto captions in the full editor transcribe the audio directly, with 176 styling presets to pick from.
Can I convert several MKV files at once?
Not in one batch. EchoWave converts one file per project, so a folder of fifty recordings means fifty passes. Rendering happens in the cloud, so your machine stays free while each file encodes, but for genuinely large batches a desktop tool with a queue, like HandBrake, is honestly the better fit.
Can I just use VLC or HandBrake instead?
For a plain format swap on your own machine, yes, both work and both are free. VLC's convert dialog is clunky but functional, and HandBrake gives fine-grained encoder control plus a batch queue. EchoWave earns its place when you are on a locked-down or low-powered machine, when you want the encode to happen somewhere other than your CPU, or when you want to trim or caption in the full editor.
What formats can this MKV converter output?
The converter outputs about 21 formats. Video: MP4, WebM, GIF, MOV, AVI, MKV, FLV, MPEG, SWF, TS, VOB, WMV and DV. Audio: AAC, AC3, AIFF, FLAC, M4A, MP3, WAV and WMA. Under Advanced you can pick the video and audio codec, such as H.264, H.265, AV1 or VP9. Converting to the same format only works if you change a codec. Higher resolutions and frame rates are editor export settings, not converter options.
Ready to convert that MKV file?
Free converter, no sign-up and no watermark, with a full editor waiting if the clip needs trimming or captions.
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