Video Format Converter

Free

Convert video files between MP4, WebM, MKV, AVI and more. No upload needed.

Drop a video here or tap to browse

MP4, WebM, MKV, MOV, AVI, FLV and more

Conversion runs entirely in your browser — files are never uploaded

Rate this tool

What is Video Format Converter?

Updated July 25, 2026

Convert video files between formats directly in your browser using FFmpeg WebAssembly — no upload, no server, fully private. Supports any input format (MP4, WebM, MKV, MOV, AVI, FLV, and more) and outputs to MP4, WebM, MKV, or AVI. The WASM engine (~32 MB) is downloaded once and cached for future use.

video convertermp4 converterwebm to mp4video formatffmpegconvert videomkvavi

Why choose Video Format Converter?

The Video Format Converter allows you to convert video files between popular formats like MP4, WebM, MKV, and AVI directly within your web browser using client-side FFmpeg WebAssembly. Because processing happens locally on your device, your files are never uploaded to a remote server, ensuring complete privacy. It eliminates the need to install heavy desktop software and provides a free, convenient way to handle standard format conversion tasks.

Best for

Quickly changing video formats without uploading files to third-party servers
Users needing a free, no-install solution for common formats like MP4, MKV, and AVI
Privacy-conscious individuals handling sensitive or personal video recordings
Lightweight video format adjustments directly in the browser

Good to know: Very large video files or heavy batch conversion workflows may experience performance limitations depending on your device's browser resources and hardware capabilities.

How to Use Video Format Converter

Convert video files between formats like MP4, WebM, and MKV privately in your browser using FFmpeg WebAssembly.

1
Open the Video Format Converter tool
Navigate to the Video Format Converter page to initialize the FFmpeg WebAssembly engine in your browser.
2
Select your local video file
Click the upload area to choose a video file from your device; the file remains private and is never uploaded to a server.
3
Choose your desired output format
Select your target format such as MP4, WebM, MKV, or AVI from the available conversion options.
4
Start the browser-based conversion process
Click the convert button to begin processing the file locally using your computer's resources via the WASM engine.
5
Download your converted video file
Once the conversion is complete, save the newly formatted video file directly to your device.

Estimated time: PT2M

Frequently Asked Questions

What is the Video Format Converter and how does it work?

The Video Format Converter is a browser-based tool that allows you to change video file formats using FFmpeg WebAssembly technology. Unlike traditional converters, it processes your files locally on your device rather than uploading them to a remote server.

Is this video converter free to use?

Yes, this is a free tool that allows anonymous users to perform up to 10 conversions. If you need more, authenticated users can perform up to 50 conversions within the set rate limits.

Which video formats are supported for conversion?

You can input almost any video format, including MP4, WebM, MKV, MOV, AVI, and FLV. The tool can output your files into four primary formats: MP4, WebM, MKV, or AVI.

Are my video files uploaded to a server?

No, your videos are never uploaded to our servers, ensuring total privacy. All processing happens directly in your web browser using a local WASM engine, so your data stays on your machine.

Do I need to download any software to use this tool?

There is no software to install; you only need a modern web browser. The tool automatically downloads a small FFmpeg WASM engine of approximately 32 MB, which is then cached for faster use in the future.

Can I use this tool to convert WebM to MP4?

Yes, this tool is specifically designed to handle conversions like WebM to MP4. Simply select your WebM file and choose MP4 as your desired output format for a quick, browser-side conversion.

What are the limitations of this browser-based converter?

While highly versatile, the tool is subject to rate limits of 10 uses for anonymous users and 50 for authenticated users. Additionally, performance depends on your device's hardware since the conversion happens locally in your browser.