Why won't my video upload to YouTube Shorts? Causes & fixes
Check the error in the YouTube Shorts composer first, then compare file size, duration and format with the requirements for that upload surface. These checks narrow the cause; they do not certify an upload.
Check these first
- File-size reference: 256 GB overall upload cap
- Duration reference: up to 3 minutes for a Short
- Check the current composer for account or surface restrictions
- Read the exact error; check connectivity and whether the original plays locally
- Filename extension is only a label; use a media inspector for the actual container and codec
Likely causes
- File is over the size limit
Compare the exact file size with the limit for your account and upload surface: 256 GB overall upload cap. A failed upload alone does not identify its cause.
- Video is longer than allowed
Reference duration: up to 3 minutes for a Short. Confirm that this applies to your account and composer before trimming a copy.
- the source container may not match the upload requirements
Check the documented formats for the exact upload surface. A filename alone does not prove the internal container or the cause of rejection. A MP4 export is a fallback to test, not a guarantee.
- The export itself is incomplete or corrupted
An interrupted export, a killed app, or a file copied while still writing can look fine in a file browser but fail to open or upload anywhere. Re-export from the original source rather than re-trying the same file.
Fix it
- Compress it
Try a smaller output preset on a copy, then check the generated size and quality. Re-encoding can lose detail and does not guarantee a smaller file or platform acceptance. This tool accepts files up to 100 MB. For a larger source, export a smaller copy in your local editor first.
Compress a video - Trim it to the limit
Confirm the current duration limit for your account and upload surface, then trim a copy to that limit. Editing presets are not proof of eligibility. The linked browser tool accepts files up to 100 MB; use a local editor for larger sources.
Trim video - Convert it to MP4
This browser converter accepts files up to 100 MB, re-encodes them and can lose quality. Convert a copy from the original and preview the generated video and audio before uploading it yourself.
Convert to MP4
Check your file
Extension and MIME type are labels, not proof of the container. Dimensions and duration come from this browser's media reader. This does not detect codecs, bitrate, corruption or platform upload compatibility. Files and measurements are not sent anywhere.
Platform reference and evidence
These reference values have partial source coverage. Ratios and dimensions are editing guidance; account and upload-surface limits can differ. Approximate or unknown values do not certify eligibility.
- Platform
- YouTube Shorts
- Editing ratio
- 9:16 or 1:1
- Max length
- up to 3 minutes
- Max file size
- 256 GB overall upload cap; Shorts duration rules still apply
Duration and size: reference and limitations. Approximate values still need confirmation in your composer.
Format reference scope: YouTube video uploads; Shorts also requires an eligible shape and duration. Source checked 2026-09-12; this does not verify every reference field. YouTube supported file formats
Prepare a copy in Koldflux, review its output and check the current destination requirements before publishing.
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