Turn WMV files into MP4 in a couple of clicks. WMV is Microsoft's legacy streaming container; MP4 is the default video container of the internet. Some detail is discarded to fit the target format; how much depends on the format and your settings.
Drop your files here
WMV files (.wmv, .asf) · up to 512 MB each
or paste files from your clipboard
Ready when you are
Drop a WMV file above and FileTools360 will turn it into MP4 — right here on your device, without uploading anything.
Drag them onto the drop area, choose them from your device, or paste them from your clipboard. You can queue several at once. Nothing is sent anywhere — the file stays on this device.
The defaults suit most people. Open Advanced to control codec, resolution and bitrate and the audio track.
Press Convert. Everything happens on your own device — nothing is uploaded. Download files one by one, or grab them all as a ZIP.
Privacy, in plain words
What “uploaded” normally means. On most online converters, pressing the button copies your file across the internet onto a computer owned by that website. That copy is what the word “upload” means, and it is the part nobody explains.
What happens instead. This site does not do it. There is no server here that receives files, so your WMV file is read, converted and handed back by the browser you are using right now. It never travels — so there is no copy to store, read, leak or hand over.
Check it yourself in ten seconds
Turn off your Wi-Fi after this page has loaded, then convert a file anyway. It still works, because everything needed is already on your device.
The longer explanation of how this works, and the full detail of what is and is not stored on the privacy page.
Video is the format where the thing being converted is usually a recording of people, and often of people who did not expect a third party to have a copy. It matters more than it sounds, because of what video files usually are:
Interviews
sources and participants who consented to you, not to a website
Security-camera footage
your home or premises, and who was in it
Family videos
children, addresses, the inside of your house
Medical or therapy consultations
clinical recordings under strict handling rules
A file that is never sent cannot be kept, leaked, subpoenaed or used to train anything. That is a property of how this works, not a promise about how carefully it is run.
WMV is Microsoft's Windows Media video container, tied to Windows Media Player and rarely supported elsewhere.
MP4 is a container, not a codec. It usually holds H.264 video and AAC audio, and that specific combination is the closest thing the internet has to a universal video format.
The two formats solve different problems, which is why converting between them involves trade-offs rather than a straight upgrade.
| Property | Source | Target |
|---|---|---|
| Compression | Container (depends on codec) | Container (depends on codec) |
| Animation | Yes | Yes |
| Introduced | 1999 | 2001 |
| Browser support | Windows only, and shrinking. | Plays on effectively every device. |
People make this switch when they run into the limits of WMV: sharing with anyone not on Windows. MP4 is the better fit when you want the video to simply play, anywhere, for anyone.
MP4 compresses without discarding data, but it cannot represent everything a WMV file holds. What does not fit is discarded permanently, so converting the result back will not restore it. Keep the WMV original if it is the only copy.
“MP4” tells you nothing about quality. An MP4 can hold anything from a pristine 4K master to a heavily compressed clip.
On every sample measured, the MP4 came out smaller — 6% smaller at worst and 1.8× smaller at best.
| Sample | WMV in | MP4 out | Change |
|---|---|---|---|
| An easy clipThe compressible end of the range — a clean tone, or a moving test pattern — where a codec does its best work. | 160 KB | 88.2 KB | −45% |
| A hard clipThe other end — pink noise, or dense video grain. Close to incompressible by design, and the worst case for every codec. | 982 KB | 927 KB | −6% |
Produced by this site's own converter. The same code that runs in your browser, at the same default settings, so these are the bytes you would download.
Samples are generated from a fixed seed rather than taken from real photographs or documents, so the corpus is reproducible and carries no licensing question — and so the numbers predict the shape of your result rather than its exact size. Measured 2026-10-01. The method, and the command that regenerates every figure on this page, are on the how it works page.
Source
Microsoft's legacy streaming container.
Target
The default video container of the internet.
Legacy container. FileTools360 decodes it and re-encodes to a modern codec, so the result is future-proof.
Good to know
Runs entirely in your browser
527 converters and tools65 file formatsnothing ever uploaded.