diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/calendars/entities/ResourceCalendar.java b/navalplanner-business/src/main/java/org/navalplanner/business/calendars/entities/ResourceCalendar.java
index e3daefe1c..12b2c3013 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/calendars/entities/ResourceCalendar.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/calendars/entities/ResourceCalendar.java
@@ -37,6 +37,9 @@ public class ResourceCalendar extends BaseCalendar {
     private Integer capacity = 1;
 
     public Integer getCapacity() {
+        if (capacity == null) {
+            return 1;
+        }
         return capacity;
     }