WEBM to MP4
WebM is a web-native video format built for browsers and streaming, using the VP8, VP9, or AV1 codecs. It is efficient and open, but that is exactly the problem once you move off the web: many phones, editing apps, messaging tools, and older devices can't play WebM at all. MP4 with H.264 is the format everything supports. Converting WebM to MP4 re-encodes the VP9 or VP8 video into H.264 so it opens in iMovie, plays on an iPhone, and uploads to platforms that reject WebM. FluidConvert does the conversion right in your browser, free, with no account and no watermark, turning a downloaded or exported WebM clip into a file you can actually use and share anywhere.
Drop your file here, or browse
Accepts: video/webm, .webm · Max 1GB · always free
Your files are encrypted with TLS and automatically deleted after conversion.
Simply upload your .WEBM file and we'll convert it to .MP4 format — fast, free, and secure.
Fast & Free
Convert files up to 1GB completely free. No account, no limits.
Secure
Files are encrypted and automatically deleted after conversion.
High Quality
Industry-leading conversion with no quality loss.
How to Convert WEBM to MP4
Upload Your File
Click the upload area above or drag and drop your .WEBM file. We support files up to 1GB, completely free.
Choose Output Format
Select .MP4 as your target format. Adjust any conversion settings if needed.
Download Your File
Click Convert Now and wait a few seconds. Once complete, download your converted file instantly.
About WEBM to MP4
Last updated: August 2026
What is WebM?
WebM is an open, royalty-free video container Google launched in 2010, designed specifically for the web and HTML5 video. It pairs the VP8, VP9, or newer AV1 video codecs with Vorbis or Opus audio, all free of licensing fees. That makes WebM the format of choice for browser video, and many sites, screen recorders, and download tools export it by default. Its strength is efficient, license-free streaming inside browsers. Its weakness is that support largely stops there: Apple devices, most mobile video apps, standard editing software, and messaging platforms often can't open WebM without conversion.
Why convert to MP4?
MP4 with H.264 is understood by essentially every device and application, which is exactly where WebM falls short. If you downloaded a WebM clip, recorded one in a browser tool, or exported one from a web app, you often can't play it on an iPhone, import it into iMovie or Premiere, send it through iMessage, or upload it to a platform that demands MP4. Converting to MP4 bridges that gap. The video looks the same, but it now works in the huge ecosystem of hardware and software that never adopted WebM's VP codecs.
What to expect from the conversion
WebM to MP4 requires re-encoding because MP4 doesn't support the VP8, VP9, or AV1 codecs WebM uses. The video is decoded and re-compressed to H.264, which is lossy, meaning a small amount of detail is discarded. At good quality settings the visual difference is minimal. File size may go up slightly, since H.264 is less efficient than VP9 or AV1, but the tradeoff is universal playback. Audio is re-encoded from Opus or Vorbis to AAC. WebM's alpha transparency, if present, is not preserved in a standard MP4.
How FluidConvert handles it
Your WebM is decoded from its VP codec and re-encoded to H.264 MP4 on secure servers that prioritize keeping the image sharp. Uploads are encrypted in transit and automatically deleted from our servers about an hour after processing. The conversion is free, needs no account, and adds no watermark.
Common reasons to convert WEBM to MP4
- Making a WebM clip downloaded from the web playable on an iPhone, iPad, or Mac
- Converting a browser screen recording saved as WebM into an editable MP4 for iMovie or Premiere
- Sending a WebM video through iMessage or another app that only accepts MP4
- Uploading a WebM export to a platform or CMS that requires MP4 video
- Turning a WebM saved by a web app into a standard file friends and colleagues can open
Frequently Asked Questions
Why can't I open a WebM file on my iPhone or Mac?
Apple's ecosystem doesn't natively support the WebM container or its VP8, VP9, and AV1 codecs. QuickTime, Photos, and iMessage typically refuse WebM files or fail to play them. Converting to MP4 with H.264 video gives you a file that opens and plays natively across macOS and iOS, so you don't need to install VLC or another third-party player.
Is WebM to MP4 conversion lossy?
Yes. MP4 can't hold WebM's VP9 or VP8 video, so the footage must be decoded and re-encoded to H.264, which discards some data. At reasonable quality settings the loss is hard to see. You are trading a slight, usually invisible quality reduction for compatibility with the vast range of devices and apps that can't play WebM.
Will my MP4 be larger than the WebM I started with?
Often slightly, yes. VP9 and AV1 in WebM are more efficient codecs than H.264, so encoding the same footage as MP4 can take a bit more space at matching quality. The increase is usually modest, and the gain is that the file now plays everywhere. If small size is critical, keep the WebM for web use and use the MP4 for playback and sharing.
Does WebM to MP4 keep transparency?
No. WebM can store an alpha channel for transparent video, but standard MP4 with H.264 does not support transparency. If your WebM has a transparent background, the conversion will fill it, typically with black, in the MP4. Transparent video for the web is one case where you may want to keep the original WebM rather than convert it.
I downloaded a WebM from a website. How do I make it playable normally?
Many browser download and screen-recording tools save video as WebM, which then won't open in most media players or editors. Converting it to MP4 with FluidConvert produces a standard file that plays on phones, imports into editing software, and uploads to platforms that reject WebM, all without needing specialized playback software.