Javascript based Math Brain Game Demo
Total watch time
38s
at 1× speed · exactly 38 seconds at 1×
| 1× | 38s |
|---|---|
| 1.25× | 30s |
| 1.5× | 25s |
| 1.75× | 22s |
| 2× | 19s |
Embed a badge
Show the length in a README or course description — it links back here and updates itself
Markdown
[](https://playlistduration.com/video/kr-NcI1JCLQ)HTML
<a href="https://playlistduration.com/video/kr-NcI1JCLQ"><img src="https://playlistduration.com/badge/video/kr-NcI1JCLQ.svg" alt="Length: 38s" width="88" height="20"></a>Add ?speed=1.5 to the image URL for the time at that speed, ?label=Course to change the left text, or ?style=flat-square for square corners.
Want the numbers themselves? GET https://playlistduration.com/api/v1/video/kr-NcI1JCLQ returns them as JSON — free, no key. API docs →
Data from the YouTube Data API as of 2026-09-22 (cached).