All 16 Gym Leader badges boost ordinary damage from moves of a matching type. Four Johto badges also boost your Pokémon's battle stats.
Johto badges control traded Pokémon obedience and permission to use HMs outside battle.
Badge Effects
Johto Badges
| Badge | Stat Boost | Move Type Damage Boost | Traded Pokémon Obedience | Move Outside Battle |
|---|---|---|---|---|
| Zephyr Badge Falkner | Attack +12.5% | Flying +12.5% | No change | Flash |
| Hive Badge Bugsy | None | Bug +12.5% | Through level 30 | Cut |
| Plain Badge Whitney | Speed +12.5% | Normal +12.5% | No change | Strength |
| Fog Badge Morty | None | Ghost +12.5% | Through level 50 | Surf |
| Storm Badge Chuck | None | Fighting +12.5% | Through level 70 | Fly |
| Mineral Badge Jasmine | Defense +12.5% | Steel +12.5% | No change | None |
| Glacier Badge Pryce | Special Attack +12.5%; Special Defense +12.5% when the bug allows it Special Defense bug | Ice +12.5% | No change | Whirlpool |
| Rising Badge Clair | None | Dragon +12.5% | All levels | Waterfall |
Kanto Badges
| Badge | Stat Boost | Move Type Damage Boost | Traded Pokémon Obedience | Move Outside Battle |
|---|---|---|---|---|
| Boulder Badge Brock | None | Rock +12.5% | No change | None |
| Cascade Badge Misty | None | Water +12.5% | No change | None |
| Thunder Badge Lt. Surge | None | Electric +12.5% | No change | None |
| Rainbow Badge Erika | None | Grass +12.5% | No change | None |
| Soul Badge Janine | None | Poison +12.5% | No change | None |
| Marsh Badge Sabrina | None | Psychic +12.5% | No change | None |
| Volcano Badge Blaine | None | Fire +12.5% | No change | None |
| Earth Badge Blue | None | Ground +12.5% | No change | None |
Stat Bonuses
The Zephyr Badge boosts Attack, the Plain Badge boosts Speed, and the Mineral Badge boosts Defense. The Glacier Badge boosts Special Attack and can boost Special Defense, subject to the bug below.
Each bonus adds one eighth of the stat, rounded down, and caps the result at 999. For example, 80 Attack becomes 90 with the Zephyr Badge. The bonuses apply to your active Pokémon in ordinary battles, including wild encounters. They do not change the stats shown on the party screen.
Badge stat and type bonuses do not apply in link battles or Crystal's Battle Tower.
Type Damage Bonuses
Each badge boosts damage from your moves of its matching type. The Pokémon's own type does not matter. The Zephyr Badge, for example, boosts Flying moves used by any of your Pokémon. No badge boosts Dark moves.
The game adds one eighth of the calculated damage, rounded down, with a minimum addition of 1. It applies this bonus before the same-type attack bonus, type effectiveness, and random damage variation. Rounding means the final damage increase may differ slightly from 12.5%.
Moves with fixed or special damage calculations skip this bonus. These include Seismic Toss, Night Shade, Dragon Rage, Sonic Boom, Psywave, Super Fang, Counter, Mirror Coat, Bide, Future Sight, and one-hit KO moves. Struggle also skips the bonus.
Traded Pokémon Obedience
Without an obedience badge, traded Pokémon obey through level 10. The Hive Badge raises that limit to 30, the Fog Badge to 50, and the Storm Badge to 70. The Rising Badge makes traded Pokémon obey at all normal levels through 100.
Pokémon with your Trainer ID obey regardless of level. Above the badge limit, a traded Pokémon has a chance to disobey each turn. Obedience checks do not apply in link battles or Crystal's Battle Tower.
Field Moves
A badge gives permission to use its listed HM move outside battle. You still need a Pokémon that knows the move. Rock Smash, a TM in these games, does not require a badge.
Pokémon League and Mt. Silver
You need all eight Johto badges to pass the gate toward Victory Road and the Pokémon League. After collecting all 16 badges, speak to Professor Oak in Pallet Town to open the route to Mt. Silver.
Badge Bugs and Battle Interactions
The Glacier Badge's Special Defense Bug
The Glacier Badge always boosts Special Attack. Its Special Defense bonus works only when the Special Attack value immediately before the badge bonus is 206 through 432, or 661 or higher.
A Pokémon entering battle with 200 Special Attack and 160 Special Defense gets 225 Special Attack, but keeps 160 Special Defense. With 240 Special Attack and the same 160 Special Defense, it gets 270 Special Attack and 180 Special Defense.
Stat changes recalculate the badge bonuses. A change to Special Attack can move that value into or out of the affected ranges, causing the Special Defense bonus to appear or disappear.
Critical Hits
A critical hit uses unmodified attacking and defending stats when the attacker's relevant Attack or Special Attack stage is less than or equal to the defender's Defense or Special Defense stage. This bypasses the corresponding badge stat bonuses. If the attacker's stage is higher, the hit uses the modified stats, including badge bonuses.
The separate badge type damage bonus still applies to critical hits.