Intelligence (PHB)

Wizards with <U>16 or more</U> intelligence gain an extra 10% XP.
 Table 4: Intelligence
Ability Score	Number of Languages	Max Spell Level	Chance Learn Spell	Max # of Spells/Level	Illusion Immunity
1 	0 	— 	— 	— 	—
2 	1 	— 	— 	— 	—
3 	1 	— 	— 	— 	—
4 	1 	— 	— 	— 	—
5 	1 	— 	— 	— 	—
6 	1 	— 	— 	— 	—
7 	1 	— 	— 	— 	—
8 	1 	— 	— 	— 	—
9 	2 	4th 	35% 	6 	—
10 	2 	5th 	40% 	7 	—
11 	2 	5th 	45% 	7 	—
12 	3 	6th 	50% 	7 	—
13 	3 	6th 	55% 	9 	—
14 	4 	7th 	60% 	9 	—
15 	4 	7th 	65% 	11 	—
16 	5 	8th 	70% 	11 	—
17 	6 	8th 	75% 	14 	—
18 	7 	9th 	85% 	18 	—
19 	8 	9th 	95% 	All 	1st Level
20 	9 	9th 	96% 	All 	2nd Level
21 	10 	9th 	97% 	All 	3rd Level
22 	11 	9th 	98% 	All 	4th Level
23 	12 	9th 	99% 	All 	5th Level
24 	15 	9th 	100% 	All 	6th Level
25 	20 	9th 	100% 	All 	7th Level
Intelligence (Int) represents a character's memory, reasoning, and learning ability, including areas outside those measured by the written word. Intelligence dictates the number of languages a character can learn. Intelligence is the prime requisite of wizards, who must have keen minds to understand and memorize magical spells. A wizard with an intelligence score of 16 or higher gains a 10% bonus to experience points earned. The wizard's intelligence dictates which spells they can learn and the number of spells they can memorize at one time. Only those of the highest intelligence can comprehend the mighty magic of 9th-level spells.
This ability gives only a general indication of a character's mental acuity. A semi-intelligent character (Int 3 or 4) can speak (with difficulty) and is apt to react instinctively and impulsively. They are not hopeless as a player character (PC), but playing such a character correctly is not easy. A character with low intelligence (Int 5-7) could also be called dull-witted or slow. A very intelligent person (Int 11 or 12) picks up new ideas quickly and learns easily. A highly intelligent character (Int 13 or 14) is one who can solve most problems without even trying very hard. One with exceptional intelligence (Int 15 or 16) is noticeably above the norm. A genius character is brilliant (Int 17 or 18). A character beyond genius is potentially more clever and more brilliant than can possibly be imagined.
However, the true capabilities of a mind lie not in numbers—I.Q., intelligence score, or whatever. Many intelligent, even brilliant, people in the real world fail to apply their minds creatively and usefully, thus falling far below their own potential. Don't rely too heavily on your character's intelligence score; you must provide your character with the creativity and energy they supposedly possess!
Number of Languages lists the number of additional languages the character can speak beyond their native language. Every character can speak their native language, no matter what their intelligence is. This knowledge extends only to speaking the language; it does not include reading or writing. The DM must decide if your character begins the game already knowing these additional languages or if the number shows only how many languages your character can possibly learn. The first choice will make communication easier, while the second increases your opportunities for role-playing (finding a tutor or creating a reason why you need to know a given language). Furthermore, your DM can limit your language selection based on their campaign. It is perfectly fair to rule that your fighter from the frozen wastes hasn't the tongues of the southlands, simply because they have never met anyone who has been to the southlands.
If the DM allows characters to have proficiencies, this column also indicates the number of extra proficiency slots the character gains due to their intelligence. These extra proficiency slots can be used however the player desires. The character never needs to spend any proficiency slots to speak their native language.
Max Spell Level lists the highest level of spells that can be cast by a wizard with this intelligence.
Chance to Learn Spell is the percentage probability that a wizard can learn a particular spell. A check is made as the wizard comes across new spells, not as they advance in level. To make the check, the wizard character must have access to a spell book containing the spell. If the player rolls the listed percentage or less, their character can learn the spell and copy it into their own spell book. If the wizard fails the roll, they cannot check that spell again until they advance to the next level (provided they still have access to the spell).
Maximum Number of Spells per Level (Optional Rule)
This number indicates the maximum number of spells a wizard can know from any particular spell level. Once a wizard has learned the maximum number of spells they are allowed in a given spell level, they cannot add any more spells of that level to their spell book (unless the optional spell research system is used). Once a spell is learned, it cannot be unlearned and replaced by a new spell.
:For example, Delsenora the wizard has an intelligence of 14. She currently knows seven 3rd-level spells. During an adventure, she finds a musty old spell book on the shelves of a dank, forgotten library. Blowing away the dust, she sees a 3rd-level spell she has never seen before! Excited, she sits down and carefully studies the arcane notes. Her chance to learn the spell is 60%. Rolling the dice, Delsenora's player rolls a 37. She understands the curious instructions and can copy them into her own spell book. When she is finished, she has eight 3rd-level spells, only one away from her maximum number. If the die roll had been greater than 60, or she already had nine 3rd-level spells in her spell book, or the spell had been greater than 7th level (the maximum level her intelligence allows her to learn), she could not have added it to her collection.
Illusion Immunity is gained by those with exceptionally high intelligence scores. Those with the immunity notice some inconsistency or inexactness in the illusion or phantasm, automatically allowing them to make their saving throws. All benefits are cumulative, thus, a character with a 20 intelligence is not fooled by 1st- or 2nd-level illusion spells.