"GeolTime" hosts a web page contextualizing absolute ages against the geological timescale, created to accompany Wikipedia articles. See its discussion page on Wikipedia.
The project is hosted at https://geoltime.github.io/
To view a specific date or range, use https://geoltime.github.io/?Ma=1234-123
Feel free to post any questions by opening a new issue, or to propose any changes to the code yourself via a pull request.