WebM to MP4 Converter
Choose a WebM file and convert it to an MP4 with AVC video and AAC audio. Processing stays on your device.
More private browser video tools
Edit or convert one video without sending it to an Instasize processing server. Codec support and processing speed depend on the browser and device.
Edit video
Convert to MP4
Related tools
Same job on a different file type or batch size. Each tool still processes the file in this browser.
Convert WebM video to MP4
WebM input
This route accepts .webm files. WebM commonly contains VP8 or VP9 video with Opus or Vorbis audio, but exact codec support depends on the browser.
MP4 output
The video and retained audio are re-encoded into an MP4 with AVC and AAC when the required browser codecs are available.
Preview the conversion
Check the complete result for sync, color, dimensions, and sound before using it in another app or website.
Output, privacy, and compatibility
Private processing
The selected video is read and processed in this browser with MediaBunny. This workflow does not upload the video to an Instasize processing server.
MP4 output
Completed edits download as MP4 files with AVC video and AAC audio when audio is retained. Re-encoding can change file size and visual quality.
Browser limits
Codec support, speed, and memory limits vary by browser and device. Keep the original file and review the complete result before deleting or publishing anything.
How to convert WebM to MP4?
- 1
Step 1: Choose a WebM file
Select one .webm video up to 200MB.
- 2
Step 2: Convert
Create an MP4 locally in the browser.
- 3
Step 3: Preview
Play the result and check its video and audio.
- 4
Step 4: Download
Save the MP4 without changing the source WebM.
One of my go-to apps
Great app for filtering photos and even greater app for sizing pictures for not only posts but story photos as well... love this app I mainly use insta size for all my posts now ;)
Fast and Straightforward
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Great Sizes
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Always helpful when needing to resize photos
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Does WebM to MP4 keep transparency?
No. The MP4 output uses AVC video and does not preserve a transparent WebM alpha channel.
Does the converter keep WebM audio?
It retains a supported primary audio track by converting it to AAC. Unsupported audio codecs may prevent a complete conversion.
Which videos are supported?
The tool accepts common video files up to 200MB. Successful decoding and MP4 encoding depend on the source codec and the video capabilities available in your browser.
Is my video uploaded?
No. This workflow processes the selected file locally in your browser. The video is not sent to an Instasize processing server.
Is this video tool free?
Yes. The browser workflow is free to use and does not require an account before processing or downloading a result.
Instasize pricing: free editing and paid AI plans
Resize, crop, add text and work with layers for free. Paid plans include an AI usage allowance, background removal and access to image and video models. First-time subscribers can start with a free trial.
Free
Essential tools for casual creators.
Free forever
- Resize, crop, text and layers
- Batch resize & convert, 200 photos at a time
- HD export
- No AI features: AI edits are part of Pro
Pro
PopularEssential AI tools for creators
Billed monthly
Annual option: $299.99 billed yearly.
- More AI usage
- Batch background removal, 200 photos at a time
- 2 generations at a time
- AI Chat Editing
- All AI image models
- All AI video models
Ultimate
Advanced features for professionals
Billed monthly
Annual option: $499 billed yearly.
- More AI usage
- Batch background removal, 200 photos at a time
- 4 generations at a time
- AI Chat Editing
- All AI image models
- All AI video models
Max
Maximum power and speed
Billed monthly
Annual option: $2199 billed yearly.
- More AI usage
- Batch background removal, 200 photos at a time
- 8 generations at a time
- AI Chat Editing
- All AI image models
- All AI video models
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