IVs (0–31 each)
HP
Atk
Def
SpA
SpD
Spe
Hidden Power type
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Base power
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The Hidden Power formula
Hidden Power's type is determined by the parity (odd/even) of the Pokémon's six IVs:
type_index = floor( ((a + 2b + 4c + 8d + 16e + 32f) × 15) / 63 )
where:
a = HP IV mod 2 (1 if odd, 0 if even)
b = Atk IV mod 2
c = Def IV mod 2
d = Spe IV mod 2
e = SpA IV mod 2
f = SpD IV mod 2 Result 0-15 maps to: Fighting, Flying, Poison, Ground, Rock, Bug, Ghost, Steel, Fire, Water, Grass, Electric, Psychic, Ice, Dragon, Dark. (Normal and Fairy are not possible Hidden Power types.)
Base power uses the second-lowest bit (bit 1) of each IV via a similar formula. In Gen 6+ it's fixed at 60. In Gen 1-5 it ranged from 30 to 70 depending on the IVs.
Why Hidden Power matters in older formats
Hidden Power gave Pokémon access to a coverage move outside their normal learnset. The competitive game-changers:
- HP Fire — let Modest Magnezone, Heatran, and Roserade hit Scizor, Ferrothorn, and Forretress.
- HP Ice — gave Electric-types (Raikou, Thundurus) a way to hit Dragon-types like Garchomp and Salamence.
- HP Ground — for Electric-types to OHKO opposing Electric-types like Magnezone and Mega Manectric.
- HP Fighting — niche on Roserade, Latios, and special Mewtwo to hit Tyranitar and Heatran.
Replaced by Tera Blast in Gen 9
Tera Blast — a Normal-type move that becomes your Tera type when Terastallized — fills Hidden Power's role for competitive coverage. Modest Roaring Moon with Tera Steel + Tera Blast Steel hits Iron Valiant and Iron Treads, mirroring what HP Ice / HP Ground used to do for special attackers in Gen 7.
The major difference: Tera Blast is one-time-use (you can only Terastallize once per battle), whereas Hidden Power was always available. Gen 9 wins on flexibility (any type, no IV breeding required) but loses on permanence.