A type chart shows which modifiers are applied to move types when attacking Pokémon of each type. The type chart differs depending on the generation of games it is from.

Generation I

× Defending type
                             
A
t
t
a
c
k
i
n
g

t
y
p
e
  ½×
  ½× ½× ½× ½×
  ½× ½×
  ½× ½× ½× ½×
  ½× ½×
  ½× ½×
  ½× ½× ½×
 
  ½× ½× ½× ½×
  ½× ½× ½×
  ½× ½× ½× ½× ½× ½×
  ½× ½× ½×
  ½×
  ½× ½×
 
These numbers are good for Generation I only. For the type chart used in later generations, see here.


Later generations

× Defending type
                                 
A
t
t
a
c
k
i
n
g

t
y
p
e
  ½× ½×
  ½× ½× ½× ½×
  ½× ½× ½×
  ½× ½× ½× ½×
  ½× ½×
  ½× ½× ½×
  ½× ½× ½× ½× ½× ½×
  ½× ½×
  ½× ½× ½× ½×
  ½× ½× ½× ½×
  ½× ½× ½×
  ½× ½× ½× ½× ½× ½× ½×
  ½× ½× ½×
  ½× ½×
  ½× ½× ½× ½×
  ½×
  ½× ½× ½×
These numbers are good for all generations aside from Generation I. For the type chart used in Generation I, see here.


Differences

The biggest different between the two charts is the addition of the Dark and Steel types to the second chart. Among relationships that were already in the chart, Bug was made .5x effective against Poison instead of 2x, Poison was changed from 2x to 1x against Bug, and Bug was changed from 1x to .5x against Ghost. Ghost was made super-effective against Psychic, as opposed to not effective at all. Also, Ice was adjusted to deal .5x damage to Fire as opposed to 1x.

See also