How do I convert MKV to MP4?

Upload your MKV file, choose MP4 as the output, and tap Convert Video. If the codecs are compatible, the conversion is instant and keeps full quality.

Is the video converter free?

Yes, completely free. No signup, no watermark, no limits.

Does my video get uploaded?

No. Everything happens in your browser. Your video never leaves your device.

You can upload MP4, MOV, MKV, AVI, WebM, FLV, WMV and more, and convert to MP4, MOV, MKV or WebM.

Will converting lower the quality?

When the formats are compatible, Sondra changes the container with no re-encoding, so there is no quality loss. Otherwise it re-encodes at the quality you choose.

Can I convert video on my phone?

Yes. Sondra works in mobile browsers (up to 100MB on mobile, 500MB on desktop), with no app to install.

Online Video Converter

Convert video between MP4, MOV, MKV, WebM and AVI in your browser. A free online video converter that turns MKV to MP4, AVI to MP4, MOV to MP4 and more. No upload, no signup.

Drop your video here

or click to select a file

Supports MP4, MOV, MKV, WebM, AVI, FLV, WMV and more (up to 500MB on desktop, 100MB on mobile)

Instant Never Uploaded Free

How It Works

1. Upload your video

Pick any video file. MP4, MKV, AVI, MOV, WebM and more all work, and it stays on your device.

2. Pick a format

Choose MP4 for the widest compatibility, or MOV, MKV or WebM.

3. Download

Save your converted video and you are done.

Convert video to MP4 and other formats, free

Sondra is a free online video converter that works entirely in your browser. Change MKV to MP4, AVI to MP4, or MOV to MP4 so your video plays on phones, TVs and social platforms, or convert MP4 to WebM for the web. No account, no watermark, and nothing is uploaded.

When the source and target already use compatible codecs, Sondra just rewraps the file, which is instant and keeps the exact same quality. Otherwise it re-encodes with H.264, the most widely supported video codec, or VP9 for WebM, always using a pixel format that plays everywhere. It all runs locally with FFmpeg, so your video never leaves your device.

Frequently Asked Questions

What to do next

Compress your videoMake the file smaller for upload, email or messaging.Remove background noiseClean up the audio in your video before sharing.Extract the audioSave just the sound from your video as MP3 or WAV.