There are 82 skills in Starfield, each with 4 ranks that all require one Skill Point. This means players will need 328 Skill Points in order to unlock and fully upgrade every skill. Since Skill Points are only earned by leveling up in Starfield, players will need an extraordinary amount of XP if they hope to complete their skill trees.
Source:https://www.cbr.com/starfield-how-to-grind-xp/