How to Convert to WEBM on Windows & Mac
Updated August 31, 2026
WEBM is the format you convert to on purpose: it streams small in browsers, which makes it the right choice for video embedded in web pages, and some platforms and tools simply ask for it.
Whatever you're starting from, MP4, MOV, MKV, or AVI, ConvertSave produces WEBM in the same three steps on Windows and Mac, locally and offline.
How to convert any video to WEBM
- 1
Drag your files into ConvertSave
Open ConvertSave and drag your video files into the window. You can drop one file or a whole selection at once. There is no upload step, because the files never leave your computer.
- 2
Choose WEBM as the output format
Pick WEBM from the format list. ConvertSave shows the formats that make sense for the files you dropped, so WEBM is right there.
- 3
Click Convert
Hit the Convert button. Each WEBM file is saved next to the original, so you don't have to hunt through folders to find your converted files. The originals are left untouched.
Fair warning on speed: WEBM's encoders work hard for their small files, so this conversion takes noticeably longer than most. That's the format, not the app.
MOV to WEBM for web publishing
iPhone and QuickTime footage headed for a website is the classic case: MOV in, WEBM out, and the page loads a fraction of the video weight it would have.
How to convert to WEBM for free
The 7-day free trial covers everything, and because conversion is local there's no upload cap or queue like the free converter sites impose on video.
Batch converting to WEBM
Queue every video at once and convert in one pass; each WEBM is saved next to its source. Given WEBM's slower encoding, a big batch is a good thing to start before lunch. We've tested batches of up to a thousand files.
Is converting to WEBM safe?
The risk with converting your videos to WEBM isn't the conversion itself, it's where the conversion happens. Free converter websites work by uploading your file to someone else's server. You usually can't tell who runs the server, where it is, or how long your file sticks around after the conversion finishes. For personal videos and photos that's a real privacy trade, and it's the reason so many of those sites are covered in aggressive ads.
ConvertSave does the conversion on your own computer. Nothing is uploaded anywhere. You can turn off Wi-Fi entirely and it still works, which is also the easy way to verify the claim. Your original file is never modified, and the converted copy is written right next to it.
Frequently asked questions
Why would I convert to WEBM instead of MP4?
Web pages. WEBM streams smaller in browsers, so embedded video loads faster. For playing on devices and sharing with people, MP4 is still the safer pick.
Why is the conversion slow?
WEBM's encoders trade encoding time for smaller files. That's inherent to the format, and it's why batch-and-walk-away is the right approach for large sets.
Which input formats work?
MP4, MOV, MKV, AVI, and other common video formats, mixed freely in one queue.
Do my videos get uploaded anywhere?
No. ConvertSave converts on your computer and works offline.
Is ConvertSave free?
There's a 7-day free trial with all features unlocked. After that it's $9/month, $60/year, or $129 once for a lifetime license that covers 3 personal devices on Mac and Windows.
