diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
index 14e8cdf7d..759d762f2 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
@@ -384,6 +384,9 @@ public abstract class ResourceAllocation<T extends DayAssignment> extends
                     * entry.getValue().size();
             sumTotalHours += getAssignedHours(entry.getValue());
         }
+        if (sumWorkableHours == 0) {
+            return ResourcesPerDay.amount(0);
+        }
         return ResourcesPerDay.calculateFrom(
                 sumTotalHours, sumWorkableHours);
     }