MP4 to WebM Converter

Turn an MP4 into a smaller, web-ready WebM. Free, in your browser, with no signup, no file limits, and no watermark.

Select MP4 file →

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We support most file types including: MP4, MOV, WEBM, AVI, MP3, WAV, PNG, JPEG, GIF, MKV, PDF, FLAC, TIFF!

EchoWave is used by creators, marketers, educators, and businesses to convert and edit media online.

Updated June 2026

Convert an MP4 to WebM in your browser, free and with no signup. WebM is the open format built for the web: its VP9 video and Opus audio often produce a noticeably smaller file than the same H.264 MP4 at matching quality, which means faster page loads and lighter uploads. It is the right choice when your video lives in an HTML5 player, a web page, or a platform that prefers WebM.

Free, no sign-upNo account, no trial

Runs in your browserNothing to install

Works on every devicePhone, tablet, laptop

No watermarkClean output, every time

How it works

How to convert MP4 to WebM

1
Upload your MP4
Drag your MP4 onto the converter or pick it from your device. Nothing to install.
2
Choose WebM and convert
Select WebM as the output and start. Free, with no sign-up and no watermark.
3
Download your WebM
Save the finished WebM, or open it in the editor to trim, crop, or resize it first.

Try it

Estimate your WebM

Pick a video bitrate and a length to see the WebM file size before you convert.

Video bitrate

Length5 min

1 min30 min

Estimated WebM size183MBSharp 1080p

An estimate. Real size varies with resolution, frame rate, and how much the picture moves.

The formats

MP4 vs WebM

MP4

MPEG-4 Part 14

The video format that plays everywhere

Type: Video container
Holds: H.264 video plus AAC audio, sometimes subtitles
Typical size: Large, it carries video
Plays on: Phones, browsers, TVs, almost any player

Best for:Watching and sharing video

WebM

Open video built for the web

Type: Open web video container
Holds: VP8 or VP9 video with Vorbis or Opus audio
Typical size: Small at good quality
Plays on: Chrome, Firefox, Edge, and Android

Best for:Video embedded on web pages

Will it lose quality?

When the codecs already match WebM, the converter can change the container without re-encoding, so the picture stays identical.
When the video has to be re-encoded for WebM, a high bitrate keeps it visually close to the MP4.
Converting cannot add detail the MP4 never had. The output is at best as good as the source.

Use cases

What people use it for

Play anywhereMake a clip your device supports

Video editorsGet footage your software accepts

Web videoUse a format browsers play

CourseworkHand in a standard video file

SharingSend a clip people can open

Troubleshooting

If something looks off

The WebM will not play

Some players are picky about codecs. Try it in VLC, which opens almost anything, or convert again and let the converter re-encode the video.

The file got larger

A format change can shift the size, and re-encoding at a high bitrate adds overhead. Lower the bitrate or trim the clip for a smaller file.

Audio and video drift out of sync

Re-download the source and convert again. If a long recording drifts, splitting it into shorter pieces usually fixes the sync.

FAQ

MP4 to WebM questions

Is the MP4 to WebM converter free?

Yes. EchoWave converts MP4 to WebM with no signup, no file-count limit, no trial, and no watermark. Upload your video, convert it, and download the WebM from your browser.

How do I convert MP4 to WebM?

Upload your MP4, choose WebM as the output format, and start the conversion. When it finishes, download the WebM or open it in the editor to trim, crop, or resize it first.

Will WebM be smaller than my MP4?

Usually yes. WebM's VP9 codec is more efficient than the H.264 commonly used in MP4, so at the same visual quality the WebM is often meaningfully smaller. The exact saving depends on the footage, since fast motion compresses less well than a static shot.

Does converting MP4 to WebM lose quality?

Going from MP4 to WebM re-encodes the video, so it is not pixel-for-pixel identical. At a sensible bitrate the difference is hard to notice, and the result cannot be sharper than the source MP4 since converting never adds detail that was not already there.

Why would I use WebM instead of MP4?

WebM is the open, web-first format that browsers play natively and that often loads faster because the file is smaller. It is a strong pick for video embedded on a site, background loops, and HTML5 players. For phones, TVs, and editing software, MP4 is still the safer all-rounder.

Does WebM support transparent backgrounds?

WebM with the VP9 codec can carry an alpha channel, so a video with a transparent background can stay transparent. Most MP4 footage is fully opaque, so transparency only applies if your source already has it. Support also varies by player, so test where you plan to use it.

Will the WebM play on iPhone and Safari?

Recent versions of Safari and iOS can play WebM, but support is newer and less consistent than on Chrome, Firefox, Edge, and Android. If you need a single file that plays everywhere with no surprises, keep an MP4 alongside the WebM.

Does the WebM keep the audio from my MP4?

Yes. The audio track is converted along with the video, re-encoded to Opus or Vorbis inside the WebM. The sound stays in sync and plays in any browser that supports WebM.

Does the converter work on Mac, Windows, and Chromebook?

Yes. It runs in any browser, so you can convert MP4 to WebM on macOS, Windows, Chromebook, Linux, and Android with nothing to install and no account to create.

Can I convert large MP4 videos to WebM?

Yes. There are no file-count limits on these pages, and large videos are supported. They take a little longer to upload and convert, and the VP9 encode often returns a smaller file than you started with.