How to convert Matroska (MKV) to WebM
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Upload your file
Drag and drop a file or click to select one. Keep this page open while the file uploads and converts.
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Convert Matroska (MKV) to WebM
NexMedia converts Matroska (MKV) to WebM on its own servers. Processing time depends on the file size and how busy the queue is.
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Download the converted file
When the conversion finishes, the download appears on this page. Your converted file is kept for 2 hours, then deleted.
About Matroska (MKV)
Matroska (MKV) is an open container format that can hold almost any video and audio codec, any number of audio and subtitle tracks, chapters and attachments.
It is popular for films and series with several audio languages and subtitle tracks, and for archiving video.
Many phones, browsers and TVs do not play MKV files directly, even when they support the codecs inside.
Convert MKV to WebM online free, no account required — WebM is an open, royalty-free web video format with VP8, VP9 or AV1 video and Opus or Vorbis audio.
Change MKV to WebM without losing quality — convert MKV to WebM free in your browser.
Why won't my MKV file play on my TV or phone? Most TVs and phones play MP4 or H.264 but not the Matroska container, so converting to MP4 makes the file playable on almost any device.
About WebM
WebM is an open, royalty-free video format developed by Google and based on the Matroska container. It holds VP8, VP9 or AV1 video with Vorbis or Opus audio.
It is made for the web: all major browsers play it in the HTML video element, and it is common for screen recordings and short clips.
WebM allows only its own small set of codecs, so H.264 video or AAC audio has to be re-encoded to fit.
Why convert video to WebM for a website? Browsers play it without plugins, and VP9 or AV1 compresses smaller than H.264 at the same quality, so pages load faster.
What changes when you convert MKV to WebM
- The MKV is re-encoded into WebM at the default quality settings, so the result looks close to the original but is not bit-identical.
Settings you can change
Before you convert MKV to WebM, you can adjust: Video codec, Rate control, Quality (CRF), Video bitrate, Resolution, Width, Height, Scale fit, Frame rate, Encoder preset, Audio codec, Audio bitrate, Trim start, Trim duration, and Remove metadata.
Limits
Each plan sets a maximum file size and a number of conversions per day, and video and audio files also have a maximum length. Guests can convert files up to 100 megabytes and 5 per day; a free account raises this to 500 megabytes and 25 per day; paid plans go up to 100 gigabytes.
Your converted WebM file is kept for 2 hours, then deleted.
MKV to WebM: questions and answers
Does converting MKV to WebM reduce quality?
The MKV is re-encoded into WebM at the default quality settings, so the result looks close to the original but is not bit-identical.
What is the difference between MKV and WebM?
MKV is a flexible open container for video with any number of audio and subtitle tracks. WebM is an open, royalty-free web video format with VP8, VP9 or AV1 video and Opus or Vorbis audio.
Can I change the settings when converting MKV to WebM?
Before you convert MKV to WebM, you can adjust: Video codec, Rate control, Quality (CRF), Video bitrate, Resolution, Width, Height, Scale fit, Frame rate, Encoder preset, Audio codec, Audio bitrate, Trim start, Trim duration, and Remove metadata.
Do I need an account to convert MKV to WebM?
No. You can convert MKV to WebM without an account; signing in raises the file-size and daily limits.
How long is my converted WebM file kept?
The WebM file you convert from MKV is kept for 2 hours, then deleted automatically.
When I convert MKV to WebM, is the video re-encoded?
The MKV is re-encoded into WebM at the default quality settings, so the result looks close to the original but is not bit-identical.
Will converting MKV to WebM change my original file?
No. The conversion reads your MKV and writes a new WebM file, leaving your original MKV file untouched.