Champion statistic

A champion statistic is a number indicating how well a champion can do a certain thing. These help define the assets of a champion. There are 17 official statistics, divided into four categories: Offensive, Defensive, Magic, and Movement.

Offensive

 * Armor penetration: How much the armor values of targets are reduced during physical damage calculations.
 * Attack damage: Provides the initial damage value of basic attacks and scaling on some abilities.
 * Attack speed: The rate at which a champion uses their basic attack.
 * Critical strike chance: The percent chance that a basic attack will critically strike to deal increased damage.
 * Critical strike damage: The percentage damage increase provided by critical strikes.
 * Life steal: The percentage of the damage done by a champion's basic attacks that is returned to them as health.

Defensive

 * Armor: Used to calculate the reduced damage (in percentage) taken from basic attacks and abilities that deal physical damage. Calculated by Armor/(Armor100)
 * Health: The total damage a champion may take before dying.
 * Health regeneration: The rate at which a champion's health is naturally restored.
 * Magic resistance: Used to calculate the reduced damage (in percentage) taken from abilities that deal magic damage. Calculated by Magic Resist/(Magic Resist100).

Ability

 * Ability power: Provides scaling on some abilities.
 * Cooldown reduction: The percent reduction in the time after an ability is used by a champion before it can be used again.
 * Magic penetration: How much the magic resistance values of targets are reduced during magic damage calculations.
 * Mana: The maximum mana available to a champion for casting abilities.
 * Mana regeneration: The rate at which a champion's mana is naturally restored.
 * Spell vamp: The percentage of the damage done by a champion's abilities that is returned to them as health.

Movement

 * Movement speed: The speed at which a champion moves around the map.

Increasing Statistics
All champions begin the game with a certain amount of attack damage, attack speed, armor, health, health regeneration, mana, and mana regeneration. This is called the base value of that statistic. All champions naturally increase these stats by a non-linear amount every time they gain a level.

All champions have the same formula for calculating their statistics (see below). Obviously, all champions go through the same 18 levels during the game. However, each champion and and skill has a different growth statistic (or per level coefficient). For example, the the AD growth statistic for is 3.375, but his MP growth statistic is 45. has AD and MP growth statistics of 3.0 and 40, which are different than. Currently, is the only champion who can modify his growth statistics. All other champions have fixed growth statistics.

 Statistic = b + g (n-1) (0.685+0.0175n) 


 * b = base
 * g = growth statistic
 * n = champion level

For example, starts level 1 with 613 Health (health base statistic), and his health growth statistic is 102. At level 2, the equation shows that his total health is 686.4 (n=2, g=102, and b=613).

Importantly, each champion's base statistics and growth statistics are unique. This makes a big difference on the battlefield. If a champion has low base statistics but high growth statistics, they will be weak at the game's beginning but strong at the game's end.

Two statistics that deviate from this pattern are movement speed and magic resistance. Every champion has a unique base movement speed that does not increase naturally, and every champion begins the game with exactly 30 or 32.1 magic resistance. Magic resistance is the only statistic that increases for some champions and not for others. In general, if a champion is ranged or has a ranged form, they will not gain magic resistance per level.

All other statistics have a natural value of zero and must be increased by other sources. The ways a champion may increase their statistics are varied and include runes, masteries, items, and auras. Some champion abilities increase that champion's statistics, either as a passive effect ( no longer passively raises her AD with her rework passively increases his life steal) or as an active effect ( briefly increases his movement speed and spell vamp) or as an effect that follows another action (, for example, passively increases his attack speed and doubles this bonus when he absorbs a spell).

Growth statistic per level
A champion does  not  increase his stats in a linear way. Instead, their increase in strength becomes faster and faster as they get into higher levels. The above equation can be rearranged to show this. The only thing required is the champion's new level and his growth statistic.

 StatIncrease = g (0.65 + 0.035 * NewLevel)  growth statistic for health is 83. When leveling-up from level 1 to level 2, the number in the brackets becomes 0.72 (or 72%) and her total health will increase by 59.76 (g=83 and NewLevel=2). To explain it another way, her growth statistic (83) was multiplied by 72% giving 59.76 health. However, when leveling-up from 15 to 16, the percent increase is 121% and the health increase is much higher at 100.43 health (g=83 and NewLevel=16).
 * g = growth statistic

At level 18, the champion will have accumulated 1,700% of the growth stats (17 · growth stats), so he ends with 17 · growth stats + base stats.