diff --git a/PKHeX.Core/Legality/Core.cs b/PKHeX.Core/Legality/Core.cs
index 29964e451..444403160 100644
--- a/PKHeX.Core/Legality/Core.cs
+++ b/PKHeX.Core/Legality/Core.cs
@@ -1106,6 +1106,26 @@ internal static IEnumerable<int> GetFutureGenEvolutions(int generation)
                 default: return Enumerable.Empty<int>();
             }
         }
+        internal static int GetDebutGeneration(int species)
+        {
+            if (species <= 0)
+                return 0;
+            if (species <= MaxSpeciesID_1)
+                return 1;
+            if (species <= MaxSpeciesID_2)
+                return 2;
+            if (species <= MaxSpeciesID_3)
+                return 3;
+            if (species <= MaxSpeciesID_4)
+                return 4;
+            if (species <= MaxSpeciesID_5)
+                return 5;
+            if (species <= MaxSpeciesID_6)
+                return 6;
+            if (species <= MaxSpeciesID_7_USUM)
+                return 7;
+            return -1;
+        }
 
         internal static int GetMaxLanguageID(int generation)
         {
diff --git a/PKHeX.Core/PKM/PKM.cs b/PKHeX.Core/PKM/PKM.cs
index cea9896bc..99935ecf4 100644
--- a/PKHeX.Core/PKM/PKM.cs
+++ b/PKHeX.Core/PKM/PKM.cs
@@ -321,8 +321,9 @@ public int GenNumber
                 if (VC1) return 1;
                 if (VC2) return 2;
                 return -1;
-            } 
+            }
         }
+        public int DebutGeneration => Legal.GetDebutGeneration(Species);
         public bool PKRS_Infected => PKRS_Strain > 0;
         public bool PKRS_Cured => PKRS_Days == 0 && PKRS_Strain > 0;
         public virtual bool ChecksumValid => Checksum == CalculateChecksum();