Skill Rate

 is a derived statistic in Fallout, Fallout 2, Fallout 3, Fallout: New Vegas, Fallout Tactics, Van Buren and J.E. Sawyer's Fallout RPG.

Fallout, Fallout 2 and Fallout Tactics

 * $$\text{Initial level}=(\text{IN}\times2)+5$$

The amount of skill points received on each level up is primarily dependent on the intelligence of the player. Every level of experience will give the player character skill points. It can be further modified modified by certain traits or perks, most notably the Skilled and Gifted traits, as well as the Educated perk.

Your character can also tag 3 skills. Tag skills are skills your character specializes in. Each tag skill gains +20% and increases twice as fast. With the Tag! Perk you gain an additional Tag skill.

Fallout 3

 * $$\text{Initial level}=\text{Intelligence}+10$$

As with the first two games, Intelligence is the primary modifier for the number of skill points earned. The Educated perk can be taken for 3 additional skill points per level, for a total of 23 at maximum Intelligence. Tag skills no longer increase twice as fast, instead affecting a 15 point increase in the tagged skill. This means that a total of 658 available skill points assuming Intelligence is set to 10 at the start and Broken Steel is installed. Through the use of skill books, it is possible to achieve 100 in every skill.

Fallout: New Vegas

 * $$\text{Initial level}=(\text{Intelligence}/2)+10$$

In New Vegas, the number of innate skill points remains the same at 10, but the Intelligence bonus is now halved. If Intelligence is set to an odd number, the half points will be stored and added to every other level; i.e. an Intelligence of 9 would result in skill point allowances of 14 and 15 every other level. Tag skills function the same as before. The Educated perk now only adds two points instead of three, meaning a maximum of 17 points per level (after level 4). 30 is the maximum possible level initially, the same as Fallout 3 with Broken Steel installed, but with the Dead Money add-on installed, the level cap is raised to 35.

Unlike Fallout 3, no combination of perk, SPECIAL, and skill point allocation will allow for 100 in every skill. At best, it is possible to increase the base value of eight skills to 100. By using skill magazines to gain temporary boosts from 80 to 100, that number is increased to 10.

In New Vegas, virtually all skill-enhancing perks have been removed or modified in such a way that they no longer increase the base value of a skill. Only Tag! provides a direct increase. Intense Training can increase skill points indirectly, as can implants (which are functionally identical), but not to any significant degree. In addition, the number of skill books has been drastically reduced, now averaging four per skill, though they are now worth four points with Comprehension instead of 2 as in Fallout 3.

The add-on Dead Money increases the maximum level to 35 and adds one of every type of skill book, enough points to increase at least one more skill to 100. Even taking this into account, however, it is still impossible to max out every skill.

When every DLC has come out, and raised the maximum level to 50, then it will be possible trough certain strategies, to gain a skill of 100 in every skill.

J.E. Sawyer's Fallout RPG
Skill points are gained by the formula
 * $$\text{IN}+6$$