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.

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 (I built this one)

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

Pricing

• One-time purchase; free web demo for single-file conversions.

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.