Type Matchup Chart
Here is a type matching chart that is based on attacks used in most Pokemon
Games:
Key things to remember
Any ground attack used on a flying type regardless if it's; it's second type or
first will do no damage whatsoever. This goes for the same for a normal
attacking a ghost and vice versa, this also goes for electric attacks used on
ground types, it also is the same for psychic attacks on dark, same for a poison
attack on a steel type and finally on which a fighting type attacks a ghost
type. Yes, no damage whatsoever for any of these.
To figure out a 4x basic damage attack, you check the move your going to use,
for this example. Let's say you use Earthquake, a ground move. You then analyze
the ground attack tree and check the types used by the pokemon you're battling
(when i say used I mean that it is part of) If the pokemon is a fire and rock
type, then those two teal spaces in each one is replaced for four times the
normal damage an earthquake move does. So from 100 normal damage to 400. As in
some cases vice versa for finding out 0.25 of basic damage. Again we will use
Earthquake as the example, if the pokemon your fighting is a grass and bug type.
It will then be analyzed. So you analyze the attacks damage on each type, 0.5 on
each one, it will only do 0.25 then on a grass and bug type. 25 damage is hardly
worth using on a grass bug pokemon.
Oh and one more thing. If the type your battling is part of two types and the
move your thinking of using has a basic damage white background down. That
doesn't mean that your next attack will be 2x basic damage. It will do normal
basic damage. So 100 damage for an earthquake will not be 200, but stay at 100.