diff --git a/include/data.h b/include/data.h
index ad3cf4ec1e..1d2a1291f9 100644
--- a/include/data.h
+++ b/include/data.h
@@ -114,7 +114,8 @@ struct TypeInfo
     u16 damageCategory:2;    // Used for B_PHYSICAL_SPECIAL_SPLIT <= GEN_3
     u16 useSecondTypeIconPalette:1;
     u16 isSpecialCaseType:1;
-    u16 padding:12;
+    u16 isHiddenPowerType:1; // Changing this for any type will change the distribution of all Hidden Power types from vanilla.
+    u16 padding:11;
     const u32 *const paletteTMHM;
     //u16 enhanceItem;
     //u16 berry;
diff --git a/src/battle_main.c b/src/battle_main.c
index 1a0da73142..1938cef20c 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -5966,12 +5966,15 @@ u32 GetDynamicMoveType(struct Pokemon *mon, u32 move, u32 battler, u8 *ateBoost)
                         | ((GetMonData(mon, MON_DATA_SPDEF_IV) & 1) << 5);
             }
 
-            // Subtract 6 instead of 1 below because 5 types are excluded (TYPE_NONE, TYPE_NORMAL, TYPE_MYSTERY, TYPE_FAIRY and TYPE_STELLAR)
-            // The final + 2 skips past TYPE_NONE and Normal.
-            moveType = ((NUMBER_OF_MON_TYPES - 6) * typeBits) / 63 + 2;
-            if (moveType >= TYPE_MYSTERY)
-                moveType++;
-            return ((moveType | F_DYNAMIC_TYPE_IGNORE_PHYSICALITY) & 0x3F);
+            u32 hpTypes[NUMBER_OF_MON_TYPES] = {0};
+            u32 i, hpTypeCount = 0;
+            for (i = 0; i < NUMBER_OF_MON_TYPES; i++)
+            {
+                if (gTypesInfo[i].isHiddenPowerType)
+                    hpTypes[hpTypeCount++] = i;
+            }
+            moveType = ((hpTypeCount - 1) * typeBits) / 63;
+            return ((hpTypes[moveType] | F_DYNAMIC_TYPE_IGNORE_PHYSICALITY) & 0x3F);
         }
         break;
     case EFFECT_CHANGE_TYPE_ON_ITEM:
diff --git a/src/data/types_info.h b/src/data/types_info.h
index d14012ed5c..ea962b4a44 100644
--- a/src/data/types_info.h
+++ b/src/data/types_info.h
@@ -40,10 +40,12 @@ const uq4_12_t gTypeEffectivenessTable[NUMBER_OF_MON_TYPES][NUMBER_OF_MON_TYPES]
 #undef ______
 #undef X
 
-// .generic is large enough that the text for TYPE_ELECTRIC will exceed TEXT_BUFF_ARRAY_COUNT.
-// In this array there's commented-out data such as references to type-resist berries that would otherwise would go unused.
-// However, we figured this information would be useful for users that want to add their own types as a reminder of
-// what data would they need to add in order to have their new types be fully fledged like official types.
+// Notes regarding custom data:
+// - The "generic" field is large enough that the text for TYPE_ELECTRIC will exceed TEXT_BUFF_ARRAY_COUNT.
+// - In this array there's commented-out data such as references to type-resist berries that would otherwise would go unused.
+//   However, we figured this information would be useful for users that want to add their own types as a reminder of
+//   what data would they need to add in order to have their new types be fully fledged like official types.
+// - Changing "isHiddenPowerType" for any type will change the distribution of all Hidden Power types from vanilla.
 const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
 {
     [TYPE_NONE] =
@@ -56,6 +58,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_NormalTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = TRUE,
+        .isHiddenPowerType = FALSE,
     },
     [TYPE_NORMAL] =
     {
@@ -69,6 +72,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_NormalTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = FALSE,
         //.enhanceItem = ITEM_SILK_SCARF,
         //.berry = ITEM_CHILAN_BERRY,
         //.gem = ITEM_NORMAL_GEM,
@@ -88,6 +92,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_FightingTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_BLACK_BELT,
         //.berry = ITEM_CHOPLE_BERRY,
         //.gem = ITEM_FIGHTING_GEM,
@@ -109,6 +114,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_FlyingTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_SHARP_BEAK,
         //.berry = ITEM_COBA_BERRY,
         //.gem = ITEM_FLYING_GEM,
@@ -130,6 +136,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_PoisonTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_POISON_BARB,
         //.berry = ITEM_KEBIA_BERRY,
         //.gem = ITEM_POISON_GEM,
@@ -151,6 +158,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_GroundTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_SOFT_SAND,
         //.berry = ITEM_SHUCA_BERRY,
         //.gem = ITEM_GROUND_GEM,
@@ -172,6 +180,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_RockTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_HARD_STONE,
         //.berry = ITEM_CHARTI_BERRY,
         //.gem = ITEM_ROCK_GEM,
@@ -193,6 +202,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_BugTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_SILVER_POWDER,
         //.berry = ITEM_TANGA_BERRY,
         //.gem = ITEM_BUG_GEM,
@@ -214,6 +224,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_GhostTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_SPELL_TAG,
         //.berry = ITEM_KASIB_BERRY,
         //.gem = ITEM_GHOST_GEM,
@@ -235,6 +246,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_SteelTMHM,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_METAL_COAT,
         //.berry = ITEM_BABIRI_BERRY,
         //.gem = ITEM_STEEL_GEM,
@@ -253,6 +265,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .damageCategory = DAMAGE_CATEGORY_SPECIAL,
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = TRUE,
+        .isHiddenPowerType = FALSE,
     },
     [TYPE_FIRE] =
     {
@@ -266,6 +279,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_FireTMHM,
         .useSecondTypeIconPalette = TRUE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_CHARCOAL,
         //.berry = ITEM_OCCA_BERRY,
         //.gem = ITEM_FIRE_GEM,
@@ -287,6 +301,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_WaterTMHM,
         .useSecondTypeIconPalette = TRUE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_MYSTIC_WATER,
         //.berry = ITEM_PASSHO_BERRY,
         //.gem = ITEM_WATER_GEM,
@@ -308,6 +323,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_GrassTMHM,
         .useSecondTypeIconPalette = TRUE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_MIRACLE_SEED,
         //.berry = ITEM_RINDO_BERRY,
         //.gem = ITEM_GRASS_GEM,
@@ -329,6 +345,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_ElectricTMHM,
         .useSecondTypeIconPalette = TRUE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_MAGNET,
         //.berry = ITEM_WACAN_BERRY,
         //.gem = ITEM_ELECTRIC_GEM,
@@ -350,6 +367,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_PsychicTMHM,
         .useSecondTypeIconPalette = TRUE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_TWISTED_SPOON,
         //.berry = ITEM_PAYAPA_BERRY,
         //.gem = ITEM_PSYCHIC_GEM,
@@ -371,6 +389,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_IceTMHM,
         .useSecondTypeIconPalette = TRUE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_NEVER_MELT_ICE,
         //.berry = ITEM_YACHE_BERRY,
         //.gem = ITEM_ICE_GEM,
@@ -392,6 +411,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_DragonTMHM,
         .useSecondTypeIconPalette = TRUE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_DRAGON_FANG,
         //.berry = ITEM_HABAN_BERRY,
         //.gem = ITEM_DRAGON_GEM,
@@ -413,6 +433,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_DarkTMHM,
         .useSecondTypeIconPalette = TRUE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = TRUE,
         //.enhanceItem = ITEM_BLACK_GLASSES,
         //.berry = ITEM_COLBUR_BERRY,
         //.gem = ITEM_DARK_GEM,
@@ -434,6 +455,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_FairyTMHM,
         .useSecondTypeIconPalette = TRUE,
         .isSpecialCaseType = FALSE,
+        .isHiddenPowerType = FALSE,
         //.enhanceItem = ITEM_FAIRY_FEATHER,
         //.berry = ITEM_ROSELI_BERRY,
         //.gem = ITEM_FAIRY_GEM,
@@ -454,6 +476,7 @@ const struct TypeInfo gTypesInfo[NUMBER_OF_MON_TYPES] =
         .paletteTMHM = gItemIconPalette_NormalTMHM, // failsafe
         .useSecondTypeIconPalette = FALSE,
         .isSpecialCaseType = TRUE,
+        .isHiddenPowerType = FALSE,
         // .teraShard = ITEM_STELLAR_TERA_SHARD,
     },
 };
diff --git a/test/battle/move_effect/hidden_power.c b/test/battle/move_effect/hidden_power.c
index 8ec63c21a7..3b2af8d99a 100644
--- a/test/battle/move_effect/hidden_power.c
+++ b/test/battle/move_effect/hidden_power.c
@@ -1,6 +1,33 @@
 #include "global.h"
 #include "test/battle.h"
 
+ASSUMPTIONS
+{
+    ASSUME(gTypesInfo[TYPE_NONE].isHiddenPowerType == FALSE);
+    ASSUME(gTypesInfo[TYPE_NORMAL].isHiddenPowerType == FALSE);
+    ASSUME(gTypesInfo[TYPE_FIGHTING].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_FLYING].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_POISON].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_GROUND].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_ROCK].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_BUG].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_GHOST].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_STEEL].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_MYSTERY].isHiddenPowerType == FALSE);
+    ASSUME(gTypesInfo[TYPE_FIRE].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_WATER].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_GRASS].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_ELECTRIC].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_PSYCHIC].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_ICE].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_DRAGON].isHiddenPowerType == TRUE);
+    ASSUME(gTypesInfo[TYPE_DARK].isHiddenPowerType == TRUE);
+    // Any type after Dark shouldn't be part of Hidden Power officially.
+    for (u32 j = TYPE_DARK + 1; j < NUMBER_OF_MON_TYPES; j++) {
+        ASSUME(gTypesInfo[j].isHiddenPowerType == FALSE);
+    }
+}
+
 // IV combinations sourced from https://www.smogon.com/forums/threads/hidden-power-iv-combinations.78083/
 SINGLE_BATTLE_TEST("Hidden Power's type is determined by IVs")
 {