What this tells you that a chart does not
A type chart gives you one row at a time. What a player actually needs is the
combination: a Pokémon is almost never one type, and two types multiply into
results that are not on any chart. Grass is merely super effective against Water and against
Ground, but a Water/Ground Pokémon takes quadruple from it, while Electric,
which would otherwise be its worst matchup, does nothing at all because Ground is immune.
Pick one type for a mono-type Pokémon or two for a dual type, and the board above resolves
every one of the eighteen attacking types against that pairing. The top half is what happens to
you. The bottom half is what your same-type attacks do to everyone else.
Reading the two halves
Taking damage
×4 is the row that decides games. It only appears when both of your types are
weak to the same attacking type, and it means one hit is usually fatal regardless of how much
defence the Pokémon has. If a typing has a ×4 row, that is the first thing to know about it.
×0 is the quietest advantage in the game. An immunity is not damage reduction,
it is a free switch-in, every time, forever. Ground into Electric, Ghost into Normal and
Fighting, Steel into Poison, Dark into Psychic, Fairy into Dragon, Flying into Ground.
Between them, ×½ and ×¼ are what let a Pokémon stay on the field. Count them: a typing with
five or more resistances is doing structural work for a team even if its stats are unremarkable.
Dealing damage
The lower half assumes you are attacking with your own types, which is what
same-type attack bonus rewards. It is a rough guide rather than a plan, because most Pokémon
carry a move outside their types precisely to cover what those types cannot touch. But if your
STAB is resisted by a long list, you already know which slot has to solve it.
The pairings worth memorising
A handful of type combinations are famous because the arithmetic is lopsided.
- Ghost / Dark: one weakness in the whole chart, Fairy, plus immunity to
Fighting, Normal and Psychic. Nothing else is that clean defensively.
- Steel / Flying: immune to Ground and Poison and resisting eight more
types, the longest resistance list in the game. Fire and Electric are the price.
- Water / Ground: its only weakness is Grass, and Grass hits it for ×4.
One weakness that severe is not obviously better than two mild ones.
- Dragon / Ground: immune to Electric, weak to Dragon and Fairy, and ×4
to Ice. That Ice weakness has defined how these Pokémon are played for two decades.
- Normal alone: zero resistances, one weakness (Fighting), one immunity
(Ghost). The flattest defensive typing in the game.
Where the numbers come from
The full eighteen-by-eighteen table is at the bottom of this page and is compiled from the
open Pokémon Showdown data set, the same source the team builder uses. Stellar is excluded from
the defensive side because it is a Terastallization-only type with no defensive row. Pokémon
Champions, the current competitive game, has no Terastallization at all.