WebM is a video format designed for the web that produces smaller files than MP4 or MOV

WebM is a video file format created by Google to work efficiently on websites and in browsers. It compresses video using VP8 or VP9 codecs (the technology that squeezes video down) and audio using Vorbis or Opus codecs. The result is a smaller file than you'd get from MP4 or MOV formats, which matters when you're uploading to a website, embedding in a blog post, or streaming video where file size directly affects loading speed.

WebM files end in .webm. You'll see them most often on YouTube, Wikipedia, and other sites that prioritize fast loading. Most modern browsers — Chrome, Firefox, Edge, and Opera — play WebM natively. Safari and Internet Explorer do not, which is the main reason WebM hasn't replaced MP4 as the universal standard.

If you're editing video for a website or learning video editing, understanding when WebM makes sense versus when to stick with MP4 will save you time and frustration. The choice depends on where your video will live and who will watch it.

Key Takeaways

  • WebM produces smaller files than MP4 using VP8 or VP9 video compression, which matters for web uploads and streaming.
  • Most browsers except Safari and Internet Explorer play WebM files directly, so WebM works best when you control the viewing environment.
  • Video editing software varies in WebM support — some export to WebM easily, while others require conversion after editing.
  • For websites where you control the player, WebM can reduce bandwidth costs; for sharing with unknown viewers, MP4 remains safer.

How WebM compression works differently from MP4

WebM and MP4 both compress video, but they use different methods. MP4 uses H.264 or H.265 compression, which has been the industry standard for over a decade. WebM uses VP8 or VP9, which Google developed and released as open-source (meaning anyone can use it without paying licensing fees).

In practice, VP9 compression is slightly more efficient than H.264 — it produces smaller files at the same quality level. However, VP9 takes longer to encode (compress), sometimes two to three times longer than H.264. If you're editing a five-minute video, encoding to VP9 might take 10 to 15 minutes instead of 5 minutes. This matters when you're working on tight important date or encoding many videos.

The file size difference is real but not dramatic. A one-minute 1080p video might be 50 MB as MP4 and 35 MB as WebM — a meaningful saving if you're hosting hundreds of videos, less meaningful if you're uploading one or two. The trade-off is encoding time and browser compatibility.

Which video editing software exports WebM

Support for WebM export varies widely. DaVinci Resolve (free version and paid) exports WebM directly — go to File > Export, choose WebM from the format menu, and select VP9 or VP8. Adobe Premiere Pro does not export WebM natively; you'll need to export as ProRes or another intermediate format, then convert using a separate tool like FFmpeg or HandBrake.

OBS Studio (free, used for streaming and recording) records directly to WebM and is one of the easiest routes if you're capturing screen video or live content. Shotcut (free) exports WebM. OpenShot (free) exports WebM. Final Cut Pro does not export WebM.

If your editing software doesn't export WebM, you have two options: export to an intermediate format like ProRes or H.264 MP4, then convert using free tools like FFmpeg or HandBrake, or choose a different editing tool. For beginners, DaVinci Resolve or OBS Studio are the simplest paths because the export option is built in and visible in the menu.

When to use WebM instead of MP4

Use WebM when you're uploading video to a website you control and you want to minimize file size and bandwidth costs. If you're running a video course platform, a news site, or a portfolio where you host the video player, WebM saves money on storage and makes videos load faster for viewers.

Use WebM when your audience will watch in modern browsers on desktop or Android devices. If your viewers are primarily on iPhones or iPads, or if you don't know what devices they'll use, MP4 is safer — it plays everywhere.

Do not use WebM if you're uploading to social media platforms like Facebook, Instagram, TikTok, or YouTube. These platforms accept MP4 and convert video to their own formats anyway, so the WebM advantage disappears. Do not use WebM if you're sharing a file with someone and you don't know whether their software will open it — MP4 is the safer choice.

Converting video to WebM if your software doesn't support it

FFmpeg is the most powerful free tool for converting to WebM. It runs from the command line, which intimidates beginners, but the command is straightforward. read FFmpeg from ffmpeg.org, then open your terminal or command prompt and type: ffmpeg -i input.mp4 -c:v libvp9 -b:v 1M output.webm. Replace input.mp4 with your file name and 1M with your desired bitrate (higher numbers mean better quality and larger files; 1M is reasonable for 1080p).

HandBrake is easier if you prefer a graphical interface. read it from handbrake.fr, open your video file, click the Format dropdown and select WebM, then click Start. HandBrake handles the technical details and shows you a progress bar.

VLC media player (free, installed on most computers) can also convert to WebM. Open Media > Convert/Save, select your file, choose WebM from the profile dropdown, and click Convert. VLC is slower than FFmpeg or HandBrake but requires no command-line knowledge.

File size and quality trade-offs with WebM

WebM quality depends on bitrate — the amount of data per second. A 1080p video at 1 Mbps (megabit per second) will look noticeably compressed; at 3 Mbps it will look good; at 5 Mbps or higher it will look excellent. MP4 at the same bitrate looks slightly softer because H.264 is less efficient, but the difference is small.

If you're encoding a video for web, start with 2 to 3 Mbps for 1080p and adjust based on what you see. Export a short test clip, watch it on the device where it will be viewed, and decide if the quality is acceptable. This matters more than the format choice — a well-encoded WebM at 2 Mbps will look better than a poorly encoded MP4 at 1 Mbps.

For comparison: a five-minute 1080p video at 2 Mbps is roughly 75 MB as WebM and 85 MB as MP4. The saving is real but not transformative unless you're hosting thousands of videos.

Compatibility issues and when they matter

Safari on Mac, iPad, and iPhone does not play WebM. Internet Explorer (no longer supported by Microsoft) does not play WebM. Chrome, Firefox, Edge, and Opera all play WebM on desktop and Android.

If you embed a WebM video on your website using the HTML5 <video> tag, Safari users will see a blank player or an error message. To fix this, provide both WebM and MP4 versions and let the browser choose: <video><source src="video.webm" type="video/webm"><source src="video.mp4" type="video/mp4"></video>. The browser plays whichever format it supports.

For a website where you know most visitors use Chrome or Android, WebM alone is fine. For a general audience, provide both formats or stick with MP4. For social media, use MP4 — the platform handles conversion.

Frequently Asked Questions

Can I edit a WebM file directly in video editing software?

Most editing software can import and edit WebM, but support varies. DaVinci Resolve, Shotcut, and OpenShot handle WebM smoothly. Adobe Premiere Pro may struggle with WebM import. If your software won't open a WebM file, convert it to MP4 first using HandBrake or FFmpeg, edit the MP4, then export to WebM if needed.

Is WebM better quality than MP4?

Not inherently. At the same bitrate, VP9 (WebM's newer codec) compresses slightly more efficiently than H.264 (MP4's standard codec), so WebM looks marginally better. The difference is small — usually only visible in side-by-side comparison. Quality depends more on bitrate than format.

Will WebM play on my phone?

Android phones play WebM in most browsers. iPhones and iPads do not — Safari will not play WebM files. If you're sharing a WebM file with someone and don't know their device, convert to MP4 first.

How much smaller is a WebM file than MP4?

WebM files are typically 15 to 25 percent smaller than MP4 at the same quality level, depending on the video content and encoding settings. A 100 MB MP4 might be 75 to 85 MB as WebM. The saving matters for large video libraries but is minor for single videos.

Should I use WebM for my YouTube videos?

No. YouTube accepts MP4 and converts it to its own formats for streaming. Uploading WebM offers no advantage and may cause slower processing. Use MP4 for YouTube, Facebook, Instagram, and other social platforms.