How to Post a Video on X (Twitter): Format, Length & Size
Last updated: June 12, 2026
Ever tried to post a video on X (formerly Twitter) and seen “can't upload” or “your media failed to process”? X has requirements for video format, length and size. This guide covers them and how to meet them.
X video requirements (approx.)
| Item | Guideline |
|---|---|
| Format (container) | MP4 or MOV |
| Video codec | H.264 (audio: AAC) |
| Length | Usually up to ~2 min 20 sec (longer on paid plans) |
| Size | Up to ~512MB |
| Aspect ratio | 16:9 or 1:1; 9:16 for vertical |
Why uploads fail
- Unsupported format (WebM, AVI, MKV often won't upload as-is)
- Unsupported codec (not H.264)
- Too long / too large
- Extreme aspect ratio that displays poorly
In short: if you can convert to MP4 (H.264) and keep length/size in range, most upload errors disappear.
How to fix it
① Convert to MP4 (H.264)
Convert WebM/MOV/other formats to MP4 first. Our converter runs in your browser without uploading.
② Compress if it's large
Over 512MB or slow to upload? Compress to shrink it while keeping it watchable.
③ Trim if it's too long
Over the length limit? Cut to just the highlight — a tight clip also gets more views.
💡 Vertical vs landscape: X is mostly viewed on phones, so vertical (9:16) or square (1:1) work well. Fix orientation with the rotate tool or reframe with crop.
FAQ
- Q. Can I post a WebM video on X?
- A. Often not as-is. Convert it to MP4 first.
- Q. Is my video uploaded?
- A. No — converting, compressing and trimming all happen in your browser.
- Q. Can I do this on my phone?
- A. Yes — prep it in your phone's browser, then post in the X app.