WebM → YouTube Shorts
Compress WebM for YouTube Shorts
Compressing WebM for YouTube Shorts comes down to three constraints: YouTube Shorts's 4 GB cap, its 1080:1920 resolution ceiling, and the need to output MP4 H.264 for reliable inline playback. WebM source files are typically 1080p screen recording (Loom default) at around 30 MB per minute — right at YouTube Shorts's 500 MB target. We calculate a per-clip bitrate budget from your duration, subtract 192 kbps for audio, and allocate the remainder to H.264 video at the highest quality that fits. WebM's VP8/VP9 video + Opus audio get transcoded to H.264 + AAC, since most platforms reject WebM. YouTube Shorts does not play WebM inline, so this page does a format conversion (WebM → MP4 H.264) plus the size compression in a single pass.
Where do you want to share your video?
How to compress WebM for YouTube Shorts
- 1Drag your .webm file onto the upload zone above (or browse to it).
- 2YouTube Shorts is already selected — we'll target 500 MB to stay safely under the 4 GB cap.
- 3Optionally trim to a highlight clip or switch to H.265 for 30-50% smaller files at the same quality.
- 4Download the compressed MP4 and share it on YouTube Shorts. Source file auto-deletes from our servers after 1 hour.
What to know about WebM → YouTube Shorts
- WebM's VP8/VP9 video + Opus audio get transcoded to H.264 + AAC, since most platforms reject WebM.
- Resolution is kept at up to 1920p when the bitrate budget allows.
- Trim to the highlight before you compress — every 10 seconds you cut gives remaining frames more bitrate to work with.
- YouTube Shorts's 500 MB target leaves a 5% safety margin below its 4 GB hard cap, so platform-side rejection is never an issue.
The compression math
A 1-minute WebM at 1080p screen recording (Loom default) = ~30 MB. YouTube Shorts's 500 MB target minus 192 kbps audio = ~69713 kbps video budget. H.264 at that budget kept at up to 1920p when the bitrate budget allows produces a file at the target size that plays inline on YouTube Shorts.
About WebM files
WebM is Google's open, royalty-free video format that uses VP8 or VP9 video codecs. It's widely used by browser-based screen recorders (like Loom exports), Chrome extensions, and web applications. While WebM plays natively in Chrome and Firefox, it has poor support on iOS devices and is rejected by most social media platforms. CompressYourVideo.com converts WebM to compressed MP4 (H.264), making it compatible with every device and platform. This is especially common for screen recordings from browser tools, which default to WebM output. The conversion preserves video quality while often reducing file size, since H.264 is more efficient than VP8 at equivalent quality levels.
About YouTube Shorts
Compress and format videos for YouTube Shorts. Shorts require 9:16 vertical format, up to 3 minutes, and look best at 1080×1920. Our tool crops, compresses, and outputs the right specs.
Related compression tools
Or compress WebM for a different platform