The Vault - Fallout Wiki

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The Vault - Fallout Wiki
Fallout, Fallout 2, Fallout Tactics
ModifiesNumber of new skill points per level, dialogue options, many skills
Related PerksGain (Fallout 2) Smooth Talker, Animal Friend, Educated, Empathy, Bonus Rate of Fire, Healer, Rad Resistance, Sharpshooter, Survivalist, Swift Learner, Comprehension
Related TraitsGifted
Fallout 3
ModifiesNumber of new skill points per level, Medicine, Repair, Science
Related PerksComprehension, Computer Whiz, Daddy's Boy/Daddy's Girl, Educated, Entomologist, Gun Nut, Nerd Rage, Swift Learner, Warmonger
Fallout: New Vegas
ModifiesNumber of new skill points per level, dialogue options, Medicine, Repair, Science
Related PerksComprehension, Computer Whiz, Educated, Entomologist, Nerd Rage!, Pack Rat, Retention, Swift Learner
Fallout 4
ModifiesExperience points gained
Related PerksV.A.N.S., Medic, Gun Nut, Hacker, Scrapper, Science!, Chemist, Robotics Expert, Nuclear Physicist, Nerd Rage!
Van Buren
ModifiesJournal entries
Related Perks?
Related Traits?
J.E. Sawyer's Fallout RPG
Related Perks?
Related Traits?
Gametitle-FO1.pngGametitle-FO2.pngGametitle-FO3.pngGametitle-FNV.pngGametitle-FO4.pngGametitle-F76.pngGametitle-FOT.pngGame tile Fallouit Shelter.pngGametitle-VB.pngGametitle-JES.pngGametitle-LH.pngGametitle-TORN.png

Knowledge, wisdom and the ability to think quickly. A high Intelligence is important for any character.

— Fallout In-game description

Intelligence is one of seven Primary Statistics in the SPECIAL character system.

Fallout, Fallout 2 and Fallout Tactics

Modifies: the number of new Skill Points per level, dialogue options, and many skills.

One of the unique qualities of Fallout and Fallout 2 was the difference in gameplay caused by creating a low Intelligence character. If you have a low Intelligence, many non-player characters will simply shrug you off, while others will insult or even attack you. It is possible to complete the game as an idiot, but most side-quests are impossible to do, and character growth is limited, as is the story involvement possible - while you can certainly bumble through the main quests, almost all plot details and background information will be left missing. Furthermore, due to limited-at-best non-player character interaction, almost all side-quests are unavailable. Because of this, playing as a low Intelligence character is only recommended for experienced players looking to role-play, or as a humorous replay option.

Intelligence can be raised permanently in Fallout 1 by Lorri's implants and in Fallout 2 using ACE and the Yellow memory module (+1) and by the Hubologist zeta scan in San Francisco (also +1 Luck, though you may have to save/reload to get a bonus rather than a penalty). Mentats give a temporary +2 Intelligence.

Fallout 3

Modifies: Medicine, Repair, and Science skills, as well as the number of new Skill Points per level.

Intelligence determines the number of skill points you receive each time you level up. The base number of skill points gained per level is 10+Intelligence. Skill points gained for raised Intelligence are not retroactive for past levels, so increasing this primary stat early if at all is the best. Also, temporary modifiers to Intelligence (e.g. from Night Person or Button's wig) do not affect the number of skill points gained.

Value Skill Points / Level Skill Modifiers
1 11 Medicine +2, Repair +2, Science +2
2 12 Medicine +4, Repair +4, Science +4
3 13 Medicine +6, Repair +6, Science +6
4 14 Medicine +8, Repair +8, Science +8
5 15 Medicine +10, Repair +10, Science +10
6 16 Medicine +12, Repair +12, Science +12
7 17 Medicine +14, Repair +14, Science +14
8 18 Medicine +16, Repair +16, Science +16
9 19 Medicine +18, Repair +18, Science +18
10 20 Medicine +20, Repair +20, Science +20

Intelligence-based Perks

Perk Requirement Level Additional Requirements
Daddy's Boy / Daddy's Girl 4 2
Gun Nut 4 2 Agility 4
Swift Learner 4 2
Comprehension 4 4
Educated 4 4
Entomologist 4 4 Science 40
Nerd Rage 5 10 Science 50
Computer Whiz 7 18 Science 70
Warmonger 7 26

Ways to increase Intelligence


  • If you have 3 Intelligence or less, Dean Dewey will call you a "special needs" child and escort you to a classroom.

Fallout: New Vegas

Intelligence affects skill points differently than it did in Fallout 3. The number of skill points gained each level is based on the formula 10 + (0.5 * INT) per level, including level 1, where INT is your Intelligence. If you get a non-whole number of skill points per level (e.g. 10.5 for INT 1) it will be saved for the next even level up. (See Skill Rate)

Intelligence-based perks

Perk Requirement Level Additional Requirements
Retention 5 2
Swift Learner 4 2
Comprehension 4 4
Educated 4 4
Entomologist 4 4 Survival 45
Pack Rat 5 8 Barter 70
Nerd Rage 5 10 Science 50
Computer Whiz 7 18 Science 70
Voracious Reader Lonesome RoadGametitle-FNV LR.png 7 22
Lessons Learned Lonesome RoadGametitle-FNV LR.png 6 26

Ways to increase Intelligence

  • The player will gain +2 Intelligence and +2 Perception when the sun is down with the Night Person perk.
  • The player can purchase an Intelligence Implant from the New Vegas Medical Clinic for 4000 caps. This raises Intelligence by +1, unless the player already has 10. If the player's Intelligence is low enough, they will only have to pay 3000 caps.
  • Mentats gives a temporary +2 to the stat. This does not affect skill points gained at level up, but does increase the relevant skills.
  • Party Time Mentats also add +2, and stack with regular Mentats (and vice versa) giving a temporary +4 increase. (e.g. Intelligence set at 6 can reach 10, giving 8 skill points towards Medicine, Science and Repair.)
  • Black coffee adds a temporary increase of +2, +4 or +6, increasing relative to the player's Survival skill.
  • Dr. Mobius' glasses add a temporary bonus of +2

Intelligence in quests and exploration

  • If the player has an Intelligence of 1 after choosing their SPECIAL stats at the beginning of the game, Doc Mitchell will say "Sorry, son/little lady. I fixed up your head as best I knew how. Guess I missed a spot."
  • When speaking with Arcade Gannon, if you have Intelligence of 3 or lower you can convince him to become your companion by stating "This place is really complicated and stuff. You're smart, can you help me do... stuff?".
  • If creating a character with Intelligence of 3 or less can grant 'special' Intelligence checks. If the player's Intelligence is really low, dialog options will appear to be short and monosyllabic, with barely any sentience.
  • When first meeting Ignacio Rivas at Helios One, he will ask the player what their interest in the place is. If the player's Intelligence is high, they may respond with "My interest in this place is scientific." However with a low-Intelligence player, the same option will be available as "I is scientistic."
  • If the player has a low enough Intelligence, they will admit they don't know what a fish is during a conversation with Cass.
  • An Intelligence of 6 is needed for Dr. Mobius to reveal that they are still planning how to save themselves. Old World BluesGametitle-FNV OWB.png
  • An Intelligence of 8 is needed to reveal the fact that Dr. Mobius scattered the personality chips across Big MT. Old World BluesGametitle-FNV OWB.png

Level names and statistics

Value Name Skill Points Skill Modifiers
1 Sub-brick 10.5 Medicine/Repair/Science +2
2 Vegetable 11 Medicine/Repair/Science +4
3 Cretin 11.5 Medicine/Repair/Science +6
4 Knucklehead 12 Medicine/Repair/Science +8
5 Knowledgeable 12.5 Medicine/Repair/Science +10
6 Gifted 13 Medicine/Repair/Science +12
7 Smartypants 13.5 Medicine/Repair/Science +14
8 Know-it-all 14 Medicine/Repair/Science +16
9 Genius 14.5 Medicine/Repair/Science +18
10 Omniscient 15 Medicine/Repair/Science +20

Low Intelligence Characters

Fallout 1 & 2

When the Player Character in Fallout and Fallout 2 has less than 4 Intelligence, the biggest change in gameplay is undoubtedly the dialogue. Upon reaching Shady Sands, the villagers take pity on you, and Aradesh just shrugs you off. The best you can speak is in half-word sentences or gibberish.

The real downside, though, is that you have no chance to do about 90% of the side quests. No one will talk to you or even give you the time of day (Even though you have it on your Pip-Boy).

In Fallout 2, you may meet Torr, the "town simpleton of Klamath", who would normally give you a quest to under go protection of his brahmin against "the evil bugmen". He will appear highly intelligent to you, as if being stupid is a culture and language all its own, and two unintelligent people can have a complete, thought-provoking, and fully articulated conversation between them.

Another person you may have an "intelligent" conversation with in Fallout 2 is AHS-9, who becomes able to understand you after you become aligned and gives you the quest to Kill the Shi Emperor.

When talking to Algernon in the basement of New Reno Arms you can start a "childhood cop and robbers" type dialog in which you accidentally shoot and kill him.

Fallout 3

In Fallout 3, there are conversation situations where characters with low Intelligence are granted other speech options, often relating to their low intellect. However, these options are few and far between, unlike the other Fallout games where one could play the entire game as a person with low Intelligence. One instance is in Roosevelt Academy, where if you activate Dean Dewey when you have an Intelligence of 3 or lower he will deem you a "special needs" child, and escort you to a 'proper room'.

Fallout: New Vegas

In addition to alternative Intelligence checks, low Intelligence changes some dialog options when speaking to vendors and non-player characters. For example, when speaking to Miguel at Miguel's Pawn Shop, the option to start trading is "Me buy things", and when speaking with Dr. Usanagi at the New Vegas Medical Clinic, after she gives you the initial description about implants you have the dialogue option "So you sell plants?", which will cause her to re-explain the implants and suggest you take the implant to make you smarter. If you take her up on this deal she will state that she thinks "you could really benefit from it", and offer the implant at a discount.

In place of the gibberish of past games, however, the player will simply not completely understand a conversation, confuse what someone is saying with something else entirely, or not understand what situation they are currently in. In the REPCONN headquarters, for example, a character with an Intelligence of 2 or less can bypass a robot that demands a password by randomly shouting "ICE CREAM!". Normally, the player would need a Luck of at least 7 to guess this.

Low Intelligence characters attempting to do the That Lucky Old Sun quest will be granted several unique and highly entertaining dialog options when conversing with Fantastic and Ignacio Rivas. An example is when informed about the hostilities between the Followers and the NCR, the player can choose to respond, "Do Flowers and NCR bear play together?"

Fallout 4

The Idiot Savant perk means low Intelligence builds can compete with high Intelligence builds in earning experience points by randomly multiplying XP earned from various sources, with a greater chance at lower Intelligence.

Fallout 4

Intelligence is a measure of your overall mental acuity, and affects the number of Experience Points earned.

Fallout 4 loading screen hints

With the absence of individual skills, Intelligence improves the amount of experience points players receive from all sources.

Intelligence-related perks

Name Rank Level Description Base ID
1 Let Vault-Tec guide you! The path to your closest quest target is displayed in V.A.T.S. 000207d1
1 Is there a doctor in the house? Stimpaks restore 40% of lost Health, and RadAway removes 40% of radiation. 0004c926
2 18 Stimpaks restore 60% of lost Health, and RadAway removes 60% of radiation 0006fa1c
3 30 Stimpaks restore 80% of lost Health, and RadAway removes 80% of radiation 0006fa1d
4 49 Stimpaks and RadAway restore all lost health and radiation, and work much more quickly. 00065e35
Gun Nut
1 You gain access to base level and Rank 1 gun mods 0004a0da
2 13 You gain access to Rank 2 gun mods 0004a0db
3 25 You gain access to Rank 3 gun mods 0004a0dc
4 39 You gain access to Rank 4 gun mods 0016578e
1 Knowledge of cutting-edge computer encryption allows you to hack Advanced terminals 00052403
2 9 You can hack Expert terminals. 00052404
3 21 You can hack Master terminals. 00052405
4 33 When hacking, you never get locked out of a terminal when things go wrong. 001d245d
1 Waste not, want not! You can salvage uncommon components like screws, aluminum, and copper when scrapping weapons and armor. 00065e65
2 23 You can salvage rare components like circuitry, nuclear material, and fiber optics when scrapping weapons and armor. Items with favorited components are highlighted. 001d2483
1 Take full advantage of advanced technology with access to base level and Rank 1 high-tech mods. 000264d9
2 17 You gain access to Rank 2 high-tech mods. 000264da
3 28 You gain access to Rank 3 high-tech mods. 000264db
4 41 You gain access to Rank 4 high-tech mods. 0016578f
1 Any chems you take last 50% longer. Far out. 000e36ff
2 16 Any chems you take now last twice as long. 000e3700
3 32 Any chems you take now last an additional 150% longer. 000e3701
4 45 Any chems you take now last an additional 200% longer. 001d2458
Robotics Expert
1 Machines will always serve humans, if you have anything to say about it. Hack a robot, and gain a chance to power it on or off, or initiate a self-destruct. 0004d889
2 19 When you successfully hack a robot, you can incite it to attack. 00065e64
3 44 When you successfully hack a robot, you can give it specific commands. 001acf96
Nuclear Physicist
1 You've learned to split the atom... and command it. Radiation weapons do 50% more damage and Fusion Cores last an extra 25% longer. 001d246f
2 14 Radiation weapons now do double damage and Fusion Cores last an extra 50% longer. 001d2470
3 26 Fusion Cores can be ejected from Power Armor like devastating grenades and Fusion Cores last twice as long. 001d2471
INT 10
Nerd Rage!
1 Genius. Is. ANGRY! When your Health drops below 20%, time slows and you gain +20 Damage resistance and do 20% more damage while the effect lasts. 0004d886
2 31 You now gain 30 more Damage Resistance and do 30% more damage while Nerd Rage is in effect. 00065e37
3 50 You now gain 40 more Damage Resistance and do 40% more damage while Nerd Rage is in effect. Kills you make while enraged restore some lost Health. 00065e38

Ways to increase Intelligence


Notable quotes

Fallout 2

  • "-(Stares in shock.)…another postnatally-aborted wreck in a post-holocaust world replete with idiot man-children. (Raises his fists.) Out of my shop! Get out at once! Don't you come back, you hear?!
    -[Chosen One] hate you! [Chosen One]…*sniff*…go get big brother to beat you up, old man! Then we'll have ice cream and…*sniff*…CAKE and a big party with clowns and…"
    (The Chosen One after exposing himself to Renesco.)
  • "Most people have evil spirits. You? You have stupid spirits. Go see shaman, get hole in head... Big hole... Very big... Huge." (Sulik)
  • "Hep Torr hep moo-moo. (Yes, of course I’ll help you fend of the predation of your family’s brahmin by these nefarious bugmen.)" (A spinet of the Chosen One's conversation with Torr.)

Fallout: New Vegas


  • If the player has an Intelligence of 8 or higher while having no stats at 1 or a Luck of 10/1, Doc Mitchell will say "Look at that. Maybe them bullets done your brain some good.".
  • If the player has an Intelligence of 1, Doc Mitchell will say "Sorry son, I fixed up your head as best I knew how, guess I missed a spot.".


The higher the character’s Intelligence, the more skills the character will excel in, and the more options he will have in dialogue. The number of skill points the character receives at each experience level is based on the character’s Intelligence.[1]


  1. Lionheart: Legacy of the Crusader manual