Experience points



Experience points (or XP and experience for short) are a measurement for how the player character is progressing through the game at any given point. The player character can earn experience points mainly by killing enemies and completing quests. Experience is used primarily to determine when a character should gain a new level. Differing amounts of experience points are awarded for killing more dangerous creatures or completing more in depth quests. For example, killing a deathclaw will always give more experience than killing a radroach. Experience points can also be gained for disarming mines and traps, picking locks, hacking computers, passing speech challenges, doing sections of a quest and, in Fallout: New Vegas, completing passive challenges. Note that experience points earned are not dependent on your character level, meaning you will get a fixed amount of XP from a certain source regardless of your current level.

Fallout
XP in Fallout is a conventional type similar to Dungeons and Dragons where levels are separated by large amount of experience. For example, you need 1,000 XP to reach level 2, 3,000 for level 3, 6,000 for level 4, and so on.

Fallout 2
Fallout 2's XP system is similar to Fallout's. The only major difference is that leveling requires more XP than in Fallout.

Fallout 3 difficulty modifier
Changing the difficulty level will also change experience gained from killing enemies. On Very Hard you will receive 150% of the regular experience for a kill, while a kill on Very Easy will only yield 50%. For example, a deathclaw is worth 25 XP on Very Easy, 50 XP on Normal and 75 XP on Very Hard.

While this means that you can gain up to three times as much experience from fights on Very Hard compared to Very Easy, this is somewhat compensated by the enemies being much tougher. In the end, it depends on the player's skills and play style which difficulty setting allows for faster leveling. Some people play on Very Easy until their enemy is about to die and then change the difficulty to Very Hard and finish them off to get the XP amount from being on the Very Hard difficulty.

XP caps at level 20 on all difficulties without installation of the Broken Steel add-on. Installing the add-on increases the cap to 30.

Fallout: New Vegas
Fallout: New Vegas, however, does not reward XP increases based on the level of difficulty selected, despite the manual (PC version) stating otherwise. This somewhat alleviates the stress encountered while playing the game simultaneously on Hardcore mode, as it is not necessary to play it on Very Hard. No additional trophy/achievement is awarded to those who play the game on Very Hard nor do you gain bonus XP.

Unlike in Fallout 3, Fallout: New Vegas awards XP for kills made by companions. This increases the usefulness of followers and significantly reduces the hassle of having to compete with them for XP.

Fallout 4
Experience is awarded for kills, crafting, and accomplishing quests. The game uses a base value for all quest completion rewards, modified later by the game:

Fallout Tactics
Experience in Fallout Tactics are given to all party members, regardless of the number of members. The game does not feature difficulty modifiers, however the Tough Guy game mode can provide 100% XP bonus.

Fallout Shelter
Experience in Fallout Shelter is tied to individual dwellers rather than the player/overseer. Experience can be gained by successful rushing, stopping incidents and killing enemies, or more gradually over time.

Bugs

 * If you earn experience points, then load an older save right before they register, you will get the points in the older save. An easy way to do this is to kill multiple enemies that deal XP independently and load in between the separate XP gains.
 * It is possible that you can earn XP past where you should have leveled up but the game does not do so. You will hence be stuck at level one. Your XP counter may end up reading something like 600/200, indicating that you should have leveled up 400 XP "ago". This may happen at any level or only from the start of the game. If it happens at the start of the game, beginning a new game fixes this bug, so watch your XP meter closely.
 * : If starting a second character, the game will recognize the level 1 character as a continuation of the most recent save (typically a level 30 character). This will make the player unable to level up at some point. This can be fixed by deleting all the save files and starting a new game.
 * : This can also be solved if you follow these steps:
 * Start a new game on a different profile that has no save file from the game.
 * Go to memory under system settings and delete the most recent auto save from your bugged profile.
 * Start a new game and the bug should not occur. In the case it does, try the same process but exit the town before 200 XP is reached.