How to convert MP4 to WebM
- 1
Upload your file
Drag and drop a file or click to select one. Keep this page open while the file uploads and converts.
- 2
Convert MP4 to WebM
NexMedia converts MP4 to WebM on its own servers. Processing time depends on the file size and how busy the queue is.
- 3
Download the converted file
When the conversion finishes, the download appears on this page. Your converted file is kept for 2 hours, then deleted.
About MP4
MP4 (MPEG-4 Part 14) is a container format standardised by ISO. It usually holds H.264 or H.265 video with AAC audio, and it can also carry subtitles and chapter markers.
It is the most widely supported video format: phones, browsers, smart TVs and video sites all play it.
The video inside an MP4 is almost always compressed with a lossy codec, so every re-encode loses a little quality.
Convert MP4 to WebM online free, no account required — WebM is an open, royalty-free web video format with VP8, VP9 or AV1 video and Opus or Vorbis audio.
Change MP4 to WebM without losing quality — convert MP4 to WebM free in your browser.
Why is my MP4 file so large? MP4 video is already compressed with H.264 or H.265, so a lower bitrate or resolution shrinks the file at the cost of some quality.
About WebM
WebM is an open, royalty-free video format developed by Google and based on the Matroska container. It holds VP8, VP9 or AV1 video with Vorbis or Opus audio.
It is made for the web: all major browsers play it in the HTML video element, and it is common for screen recordings and short clips.
WebM allows only its own small set of codecs, so H.264 video or AAC audio has to be re-encoded to fit.
Why convert video to WebM for a website? Browsers play it without plugins, and VP9 or AV1 compresses smaller than H.264 at the same quality, so pages load faster.
What changes when you convert MP4 to WebM
- The MP4 is re-encoded into WebM at the default quality settings, so the result looks close to the original but is not bit-identical.
Settings you can change
Before you convert MP4 to WebM, you can adjust: Video codec, Rate control, Quality (CRF), Video bitrate, Resolution, Width, Height, Scale fit, Frame rate, Encoder preset, Audio codec, Audio bitrate, Trim start, Trim duration, and Remove metadata.
Limits
Each plan sets a maximum file size and a number of conversions per day, and video and audio files also have a maximum length. Guests can convert files up to 100 megabytes and 5 per day; a free account raises this to 500 megabytes and 25 per day; paid plans go up to 100 gigabytes.
Your converted WebM file is kept for 2 hours, then deleted.
MP4 to WebM: questions and answers
Does converting MP4 to WebM reduce quality?
The MP4 is re-encoded into WebM at the default quality settings, so the result looks close to the original but is not bit-identical.
What is the difference between MP4 and WebM?
MP4 is a widely supported video container, usually holding H.264 video and AAC audio. WebM is an open, royalty-free web video format with VP8, VP9 or AV1 video and Opus or Vorbis audio.
Can I change the settings when converting MP4 to WebM?
Before you convert MP4 to WebM, you can adjust: Video codec, Rate control, Quality (CRF), Video bitrate, Resolution, Width, Height, Scale fit, Frame rate, Encoder preset, Audio codec, Audio bitrate, Trim start, Trim duration, and Remove metadata.
Do I need an account to convert MP4 to WebM?
No. You can convert MP4 to WebM without an account; signing in raises the file-size and daily limits.
How long is my converted WebM file kept?
The WebM file you convert from MP4 is kept for 2 hours, then deleted automatically.
When I convert MP4 to WebM, is the video re-encoded?
The MP4 is re-encoded into WebM at the default quality settings, so the result looks close to the original but is not bit-identical.
Will converting MP4 to WebM change my original file?
No. The conversion reads your MP4 and writes a new WebM file, leaving your original MP4 file untouched.