18 Best MP4 to WebM Converters in 2026 (Free and Paid)

MP4 to WebM is the conversion you do when you need video specifically for the web — a landing page hero, a documentation walkthrough, a GitHub README clip, a project demo. WebM (VP9 video + Opus audio, or AV1 video + Opus) was designed by Google for the web. It gets smaller file sizes than MP4 at the same quality, plays in every modern browser without a plug-in, and avoids the patent licensing issues that haunt H.264 in some commercial contexts. The catch is that WebM encoding is slow, and the encoder settings matter a lot. This guide compares 18 MP4 to WebM converters in 2026.

How to Convert is listed first because it is made by the same indie developer who writes this blog. WebM is also one of those cases where the tool you pick determines whether the file ends up 30% smaller or 30% bigger than the source MP4 — encoder choice and settings really do matter.

VP9 or AV1? Which Codec to Pick

• VP9 — the older WebM video codec. Supported in every modern browser (Chrome since 2013, Safari since 14, Firefox always). Encoder is slow but mature. The default for most WebM tools.
• AV1 — the newer WebM video codec. Supported in Chrome, Firefox, Edge, and Safari (since 17). Files are 30–50% smaller than VP9 at the same quality. Encoder is much slower — 10–50x slower than VP9 in software, fast in hardware-accelerated encoders.

For most uses, VP9 is the right pick — universal browser support, reasonable encode time. Use AV1 only if file size really matters and you have time to encode.

Quick Picks for MP4 → WebM

• Best CLI: FFmpeg with libvpx-vp9 (VP9) or libsvtav1 (AV1).
• Best free GUI: HandBrake.
• Best for site assets: sharp / Next.js's pipeline, or a script.
• One-shot: How to Convert.
• Sensitive video: stay local.

One-shot: MP4 to WebM converter.

1. How to Convert

Drop MP4s in, pick WebM, choose VP9 or AV1, set quality, hit convert. Local.

Pricing

• One-time license; free trial.

2. FFmpeg

VP9 (recommended default):

ffmpeg -i input.mp4 -c:v libvpx-vp9 -crf 32 -b:v 0 -c:a libopus -b:a 128k output.webm

AV1 (newer, smaller files, slower):

ffmpeg -i input.mp4 -c:v libsvtav1 -crf 35 -c:a libopus -b:a 128k output.webm

Two-pass VP9 for highest quality at a given file size:

ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 2M -pass 1 -an -f null /dev/null
ffmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 2M -pass 2 -c:a libopus -b:a 128k output.webm

Pricing

• Free, open source.

3. HandBrake

Free cross-platform video transcoder. WebM output preset includes VP9 and AV1. The friendly GUI for FFmpeg-equivalent settings.

Pricing

• Free, open source.

4. Shutter Encoder

Free FFmpeg GUI with batch WebM support. Cleaner workflow than running FFmpeg in a loop.

Pricing

• Free.

5. DaVinci Resolve

Pro video editor with WebM export in the Deliver page (Studio edition). The right pick when MP4 → WebM is part of a finishing workflow.

Pricing

• Free Studio edition; paid Studio for hardware-accelerated AV1.

6. VLC

Media → Convert / Save → WebM. Functional but less control than HandBrake.

Pricing

• Free, open source.

7. Any Video Converter

Consumer video converter with WebM output.

Pricing

• Freemium.

8. Permute (Mac)

Polished Mac media converter. Drag MP4 in, pick WebM, done.

Pricing

• One-time purchase.

9. Wondershare UniConverter

Full media suite with WebM presets.

Pricing

• Paid.

10. Movavi Video Converter

Beginner-friendly paid converter with WebM output.

Pricing

• Paid.

11. Prism Video Converter

Simple paid video converter from NCH with WebM support.

Pricing

• Free home; paid commercial.

12. Kdenlive

Free open-source video editor with WebM render targets.

Pricing

• Free, open source.

13. Adobe Premiere Pro

Pro video editor. WebM export via the Media Encoder.

Pricing

• Subscription.

14. CloudConvert

Web converter. Slow for big MP4s. Stay local for sensitive video.

Pricing

• Free tier; paid above.

15. Convertio

Web MP4 → WebM.

Pricing

• Free with caps; paid above.

16. Online-Convert

Web converter with detailed WebM options including resolution and bitrate.

Pricing

• Free with limits; paid above.

17. FreeConvert

Web converter with quality slider.

Pricing

• Free with caps; paid above.

18. Zamzar

Long-running web converter.

Pricing

• Free with daily limits; paid above.

How to Choose

• Web hero / asset: FFmpeg with VP9, CRF 32. Standard quality, universal browser support.
• Smallest possible file: AV1 if you have encode time.
• GUI: HandBrake or Shutter Encoder.
• Pro pipeline: DaVinci Resolve or Premiere.
• Batch: FFmpeg in a script or How to Convert.
• Sensitive video: stay local.

Final Thoughts

MP4 → WebM is the right conversion when video is for the web specifically — smaller files, no licensing concerns, native browser playback. VP9 is the safe default for compatibility and encode time; AV1 is the choice when you have minutes-to-hours of encode time available and want the smallest possible file. FFmpeg or HandBrake handle the conversion cleanly; everything else is wrappers around the same encoders.