WebM to MP4 Converter

How to Convert WebM to MP4 Online

1. Upload Your WebM File: Drag and drop or click "Add Files" to select WebM videos. Browser screen recordings, OBS exports, YouTube/Twitter downloads, and Chrome tab captures all work. Batch is supported — drop in a folder or hold Shift to select multiple files.
2. Pick File Compression and Quality Preset: The default Quality Preset is "Very High (Recommended)" — visually transparent re-encoding to H.264 for universal playback. Switch File Compression to Specific file size to target an exact MB number, Constant Bitrate for predictable streaming bitrates, Variable Bitrate for smaller files at the same perceived quality, or Constant Quality / Constraint Quality to control the CRF directly (lower CRF = higher quality, larger file).
3. Resize or Trim (Optional): Choose a Preset Resolution (2160p / 1440p / 1080p / 720p / 480p / 360p / 240p), set Resolution Percentage to scale by a fraction of the original, or enter Width × Height manually. Use Trim → Time Range to keep just the part you need; both start and duration accept seconds (12.5) or HH:MM:SS.sss (00:01:30.500).
4. Convert and Download: Click Convert. Files are uploaded over an encrypted connection, processed on xconvert’s servers, and deleted automatically after a few hours — no sign-up, no watermark, no per-file cap.

Why Convert WebM to MP4?

WebM (VP8 / VP9 / AV1 codecs in a Matroska-derived container) is the web's native video format — efficient and royalty-free, used heavily by YouTube, Twitter/X, Reddit, Discord uploads, and most browser-based screen recorders (Chrome tab capture, Loom downloads, OBS Studio's default browser-friendly output). The drawback: WebM only plays reliably inside browsers and a handful of codec-aware apps. Almost everywhere else expects MP4 with H.264. Common reasons people convert WebM → MP4:

• Playing on phones, tablets, smart TVs, consoles, car infotainment — iOS Safari gained full WebM support in iOS 17.4, so older iPhones/iPads struggle to play WebM reliably. AirPlay, Chromecast, Roku, Fire TV, Apple TV, PlayStation, and Xbox all expect MP4 / H.264 for direct playback.
• Editing in Premiere Pro, Final Cut Pro, DaVinci Resolve, iMovie, CapCut — most desktop editors import MP4 cleanly but require plugins or proxy transcodes for WebM. Final Cut Pro and iMovie reject WebM entirely without third-party tools.
• Uploading to social media — Instagram Reels, TikTok, Facebook, LinkedIn, and X all re-encode WebM after upload, often dropping quality or producing audio sync issues. Pre-converting to MP4 (H.264 + AAC) gives you control over the source codec, bitrate, and resolution that they'll work from.
• Sharing screen recordings with non-technical users — Chrome's built-in screen recorder, Loom, and OBS often produce WebM by default. Windows Media Player, QuickTime, iMessage previews, and most email clients expect MP4; converting first avoids the "can't play this video" dialog on the receiving end.
• Embedding in PowerPoint, Keynote, Google Slides, Notion — Office apps accept MP4 with H.264 reliably; WebM imports silently fail or show a black frame. Notion's video block also prefers MP4 for inline playback across platforms.
• Discord and messaging apps — Discord plays WebM inline on desktop but not in the iOS app preview. MP4 plays universally across Discord, Slack, Teams, WhatsApp, and Telegram inline previews.

WebM vs MP4 — Format Comparison

Codec Choice for the MP4 Output

Frequently Asked Questions

Will converting WebM to MP4 reduce quality?

At default settings the quality drop is imperceptible. The conversion re-encodes from VP8 / VP9 to H.264 (or your chosen codec) — there is no direct remux because MP4 players don't reliably decode VP8 / VP9 from an.mp4 container. Set Constant Quality with CRF 18-20 for visually lossless output, or leave Quality Preset at "Very High (Recommended)" to keep every detail. The container changes from WebM to MP4 but the visual story stays intact.

Why won't my WebM play in iMovie / Premiere / PowerPoint?

These tools were built around the H.264 / MP4 ecosystem and lack out-of-the-box WebM decoders. iMovie and Final Cut Pro reject WebM outright; Premiere Pro shows an error unless you install third-party codec packs; PowerPoint and Keynote often import audio-only or show a black frame. Converting to MP4 with H.264 is the cleanest fix — it works in every editor and presentation tool without plugins.

Should I pick H.264, H.265, or AV1 for the MP4?

H.264 if you need universal playback (older Windows machines, work laptops, basic media players, embedded in email or PowerPoint). H.265 if your audience is on modern devices (any iPhone since iOS 11, Apple Silicon Macs, recent Android, Windows 10/11 with the HEVC extension) and you want roughly 40-50% smaller files. AV1 if you're archiving for the future and don't mind slower encoding — it produces the smallest files at high quality but reliably decodes only on 2022+ hardware.

Can I convert multiple WebM files at once?

Yes — drop in as many WebM files as you want. They convert in parallel on our servers and download individually or as a single ZIP. Settings can be applied uniformly or per-file. For batches of long screen recordings you may want to compress WebM first or trim before converting.

Can I trim or cut the video while converting?

Yes. Set Trim to Time Range and enter a start time and duration. Both accept seconds (12.5) or HH:MM:SS.sss format (00:01:30.500). Trim first to skip dead air at the start of a screen recording before encoding — you'll save encoding time and produce a smaller file. For more granular cuts, use the dedicated video cutter.

Will the audio convert too?

Yes. WebM uses Opus or Vorbis audio; the MP4 output uses AAC by default. Audio is re-encoded transparently — MP4 containers do not officially support Opus, so the audio track must be transcoded. If your WebM has no audio track (common with OBS screen captures recorded without mic input), the MP4 will also be silent.

What's the file size limit?

XConvert handles large WebM files including multi-GB screen recordings. Conversion runs on xconvert's servers, so the practical limit is upload size and connection speed. There is no fixed cap and no quantity limit on batch jobs.

Can I keep VP9 in the MP4 instead of re-encoding to H.264?

VP9-in-MP4 is technically defined by ISO/IEC 14496-15:2022 but poorly supported in practice — QuickTime, Windows Media Player, most TV apps, and PowerPoint will not play VP9 from an.mp4 container. For real compatibility, transcode to H.264 or H.265. If you specifically want to keep VP9, leave the file as.webm or repackage to MKV using WebM to MKV.

Is the reverse conversion supported?

Yes — see MP4 to WebM when you need a smaller, royalty-free file for web embedding or open-source workflows.