Get your video under X's file size limit
Drop a video and FitSize shrinks it to X's limit in your browser. Nothing is uploaded to a server.
Instant client-side compression · Up to 2 GB per file · Zero server upload
- Video, no Premium limit
- 512 MB
- FitSize aims for
- 512 MB
- Last checked
- 30 September 2026
- Read on
- help.x.com
X has two separate ceilings for video, and only one of them is about file size. Without Premium you are held to a short clip; with Premium the allowed length and size both jump. Which ceiling you hit first depends on your account, so it helps to know both before you compress.
Why X has this limit
Why does X reject or degrade your video? X (formerly Twitter) imposes upload limits and aggressive re-compression algorithms that introduce visual artifacts. FitSize uses the client-side W3C WebCodecs API to compress clips to optimal bitrates, preserving crisp motion clarity and guaranteeing fast playback with zero-byte server upload privacy.
X's help page states the limits by plan and does not explain them. The pattern it shows is that length and size are tied to Premium: an account without Premium can upload videos up to 140 seconds long and 512 MB, while Premium accounts can upload videos shorter than 4 hours at 1080p with a maximum file size of 16 GB.
Source: help.x.com
What FitSize does with your file
FitSize defaults to the limit for accounts without Premium, since that is what most accounts have, and offers the Premium limit as a one-click option. Length is not something compression can change, so if your clip is longer than the account allows, trimming it comes first; compression only helps with the file size.
Best fit for a 30-second clip at 512 MB: 1080p at Balanced quality (that resolution holds up to 12 min 56 s). Best fit for a 2-minute clip at 512 MB: 1080p at Balanced quality (that resolution holds up to 12 min 56 s).
Your file never leaves your device. It is read and compressed by your browser, and nothing is uploaded to a server.
Three things to watch on X
- Length can stop you before size does. If you are not a Premium subscriber you can upload videos up to 140 seconds long with a maximum file size of 512 MB. A longer clip needs trimming however small the file is. Source: help.x.com
- Premium changes both limits, and resolution matters. Premium subscribers can upload videos shorter than 4 hours at 1080p with a maximum file size of 16 GB, and videos between 2 and 4 hours at 720p with the same size limit. Source: help.x.com
- Trim in the app and expect a format check. X lets you trim the length of a video by dragging either side of the bar at the bottom, and on the web you are prompted if the video is not in a supported format, so a format problem shows up at upload rather than after you have compressed. Source: help.x.com
X limits by account type
| Account | Limit | Checked |
|---|---|---|
| Video, no Premium | 512 MB | 30 September 2026 |
| Video, Premium | 16 GB | 30 September 2026 |
FitSize vs traditional cloud converters
| Architecture Feature | FitSize (In-Browser) | Traditional Cloud Converters |
|---|---|---|
| Latency | Instant / 0s queue delay | 15–45s upload queue & network delay |
| Privacy | 0-Byte Server Upload (100% on-device) | Files uploaded & stored on third-party servers |
| Bandwidth | 0 MB upload bandwidth consumed | Full upload and download bandwidth consumed |
| Exact File Size Guarantee | Deterministic bit-budget target | Trial-and-error guesswork re-compression |
Frequently asked questions about X compression
What are the video file size and length limits on X (Twitter)?
Free accounts can upload videos up to 512 MB and 140 seconds in duration. X Premium subscribers can upload files up to 8 GB with durations extending up to 3 hours.
How can I prevent X from ruining my video quality?
X re-encodes uploaded videos to standard bitrates. By using FitSize to pre-encode your video with clean keyframes and compliant dimensions, you bypass severe compression degradation.
Is client-side video encoding faster than cloud converters?
Yes. Because FitSize utilizes your device's native GPU and W3C WebCodecs API, rendering occurs instantly in-memory without waiting in cloud conversion queues or uploading large files.