Tools / File Converter / WEBM to MKV Converter

WEBM to MKV Converter

Convert WEBM files to MKV. Free, without uploading.

This tool converts WEBM files to MKV. WEBM is an open video format built for the web (VP8/VP9 video, Opus audio). Browsers play it natively.

MKV (Matroska) is a flexible container that can hold several audio and subtitle tracks. It is common on computers, but phones and TVs don’t always play it. The video is re-encoded with H.264 video and AAC audio. You choose the quality and resolution, and can trim it with a start and end time.

Conversion runs on your device; your file is never sent to a server. The components download once on first use, and later conversions start right away.

How to use

1. Choose the WEBM video, drag it in, or paste its link.
2. Choose the quality and resolution; optionally enter trim times.
3. Press "Convert" and download the MKV file.

Frequently asked questions

How long does WEBM to MKV take?

It runs on your device’s processor. On a computer a one-minute 1080p video usually takes a minute or two; lowering the resolution speeds it up.

Is there a file size limit?

No fixed limit; your device’s memory decides. Computers usually handle files up to 1–2 GB.

Is my file uploaded?

No. Your WEBM file is converted to MKV inside your browser.