Gen 1 progression math
Pokemon Yellow badge boosts
Four badges multiply battle stats by ×1.125 (Boulder → Attack, Thunder → Defense, Soul → Speed, Volcano → Special). The other four raise traded mon obedience and unlock field HMs. Toggle your badges, preview stacked glitch applications, and jump to each gym guide.
Fast answer
What badge boosts actually do
In battle (not link play), the game multiplies your active mon’s matching stat by 9/8 for each of: Boulder (Attack), Thunder (Defense), Soul (Speed), Volcano (Special). Cascade / Rainbow / Marsh / Earth change obedience for traded Pokémon and unlock Cut / Strength / League access—not those four battle multipliers.
Yellow / Gen 1 gotcha
Text can disagree with the code
Gym leaders may claim Thunder boosts Speed and Soul boosts Defense. English Yellow’s battle routine applies Thunder → Defense and Soul → Speed (same layout as Red/Blue). This page uses the cartridge order from ApplyBadgeStatBoosts and the site gym dataset.
Interactive
Badge boost calculator
Toggle badges you own, enter current in-battle stats (after DV/Stat Exp/level, before boosts), then set how many times ApplyBadgeStatBoosts has run (1 = normal; higher simulates the restack glitch).
Normal battles apply once when stats are loaded. Stat-up moves can reapply.
Obedience: Traded mons obey through Lv. 10
Reference
Every badge effect
Traded Pokemon
Obedience ladder
Only Pokémon with a different OT ID use this ladder. Partner Pikachu and mon you caught yourself always obey. Values match English Yellow’s disobedience check (Earth → 101 = always obey).
| Requirement | Max level | Notes |
|---|
Trade evolutions
Haunter → Gengar and friends need a trade. Plan badges before re-importing high-level outsiders—see in-game trades and complete Pokédex guides.
EXP from trades
Traded mon still gain boosted EXP in Gen 1. Badge obedience is the trade-off if you outlevel the ladder.
Save sync
Import a save to see which badges My Run already thinks you own, then mirror them in this calculator.
Exploit
Badge Boost Glitch
How restacking happens
When you use a stat-raising move, Yellow can call the badge boost routine again on your current battle stats—multiplying already-boosted numbers by another 1.125 per owned boost badge.
Practical use
Speed badge stacks improve turn order, but they do not change critical-hit odds: Gen 1 crit checks use the species’ unmodified base Speed. Special stacks buff the unified Special stat for Fire/Water/Electric/etc. Cap remains 999.
Not required for story
The main game never needs intentional restacks. Treat the glitch as optional tech; keep a save backup if you experiment.
FAQ
Badge boost questions
Which badges boost which stats in Pokemon Yellow?
Boulder → Attack, Thunder → Defense, Soul → Speed, Volcano → Special. Each multiplies by 1.125 in non-link battles. The other badges handle obedience and HM outdoors rules.
Does the Thunder Badge boost Speed?
In-game dialogue may say so, but the battle code boosts Defense for Thunder and Speed for Soul. Plan teams using the code behavior.
Do badge boosts work in link battles?
No. ApplyBadgeStatBoosts returns immediately during link battles.
What level do traded Pokemon obey?
Without Cascade, through Lv.10; Cascade 30; Rainbow 50; Marsh 70; Earth all levels. Self-caught mon always obey.
Is the Badge Boost Glitch still in Yellow?
Yes. Stat-stage moves can reapply badge multipliers. Use the stack control above to estimate inflated stats (capped at 999).
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