WebM vs MP4 — Which Should You Export?

REEL CUTTER exports video in two formats: WebM and MP4. Both produce high-quality video but they have different strengths, and the right choice depends on what you're doing with the file.

MP4 — What It Is

MP4 (MPEG-4 Part 14) is a container format that usually holds video encoded with H.264 or H.265. It's the most widely compatible video format available — supported on every operating system, every streaming platform, every device, and every browser since the mid-2000s.

WebM — What It Is

WebM is an open video format developed by Google, designed specifically for the web. It uses VP8 or VP9 video encoding. VP9 is highly efficient — it typically produces files 30–50% smaller than H.264 at comparable visual quality, which makes it ideal for streaming and download.

File Size Comparison

For a typical 30-second 1080p clip at High quality, WebM (VP9) tends to produce a smaller file than MP4 (H.264) for visually equivalent results. The difference varies depending on the content — highly detailed or fast-moving footage sees the biggest gains with VP9.

Compatibility

MP4 is universally supported. WebM is not supported on older iOS devices (before iOS 16), some smart TVs, and older versions of Safari. In 2025, most modern devices support both — but if you need guaranteed playback on all devices, MP4 is the safer choice.

Platform Support

• YouTube — Both supported. YouTube re-encodes your upload to VP9 anyway.
• Instagram — MP4 recommended. WebM support varies.
• TikTok — MP4 recommended.
• Twitter / X — MP4.
• Web embed (HTML video tag) — WebM with MP4 fallback is the gold standard.
• Email attachment — MP4 for broadest compatibility.

Processing Speed

In REEL CUTTER, WebM typically exports faster than MP4 because the browser's WebM encoder is more optimised than its MP4 pipeline. For quick exports and uploads, WebM is the faster choice.

The Simple Answer

Choose WebM if you want a smaller, faster-to-export file and your audience is on modern browsers or Android. Choose MP4 if you're uploading to a social platform, sharing via email, or need guaranteed compatibility across all devices and software.