Free Online Video Converter — MP4, MKV, WebM, MOV

Convert video formats right in your browser. No upload, no signup, completely free. Files never leave your device.

Convert MP4, MKV, WebM, and MOV files in your browser — no upload, no signup, no cost. Compatible files are remuxed in seconds; when re-encoding is needed, the conversion still runs locally, and the VidMost desktop app can do it far faster.

How to use

  1. Choose your video. Drag a file in or click to select. It stays on your device — nothing is uploaded.
  2. Pick a target format. Choose MP4, MKV, WebM, or MOV. Compatible files convert in seconds.
  3. Download. Your converted file downloads straight from your browser.

Online vs Desktop

FeatureOnlineVidMost Desktop
Max file sizeUp to 1GBUnlimited
Batch conversionOne at a timeYes
Re-encode speedSlower (browser)Hardware-accelerated
CostFreeFree

Is this video converter really free?
Yes. It runs entirely in your browser using WebAssembly — there is no upload, no account, and no cost.
Are my files uploaded to a server?
No. All processing happens locally in your browser. Your video never leaves your device.
What's the file size limit?
Files up to 1GB are supported. For very large files or batch conversion, the VidMost desktop app is faster and has no limit.