diff --git a/hibernate-core/src/main/java/org/hibernate/persister/entity/JoinedSubclassEntityPersister.java b/hibernate-core/src/main/java/org/hibernate/persister/entity/JoinedSubclassEntityPersister.java
index b387d1860f..8f98e5e3c5 100644
--- a/hibernate-core/src/main/java/org/hibernate/persister/entity/JoinedSubclassEntityPersister.java
+++ b/hibernate-core/src/main/java/org/hibernate/persister/entity/JoinedSubclassEntityPersister.java
@@ -1094,7 +1094,7 @@ public class JoinedSubclassEntityPersister extends AbstractEntityPersister {
 
 		if ( index >= subclassNamesBySubclassTable.length ) {
 			throw new IllegalArgumentException(
-					"Given subclass table number is outside expected range [" + subclassNamesBySubclassTable.length
+					"Given subclass table number is outside expected range [" + (subclassNamesBySubclassTable.length -1)
 							+ "] as defined by subclassTableNameClosure/subclassClosure"
 			);
 		}