I translated this old stamina calculator I used to use to english. Just make a copy of it.

https://docs.google.com/spreadsheets/d/1wnIiZKjLcXWhFhcTUL0G9c4oqlwIz009LmTGt8pz9bg/edit?usp=sharing

Stamina will matter more in URA Finals and PVE/PVP content outside of career. Speed skills also consume stamina so it's better to have more.