diff --git a/ReportImp/HausDuelken/Calculations/CustomGroupDurationCalculator.cs b/ReportImp/HausDuelken/Calculations/CustomGroupDurationCalculator.cs
new file mode 100644
index 000000000..88626bae8
--- /dev/null
+++ b/ReportImp/HausDuelken/Calculations/CustomGroupDurationCalculator.cs
@@ -0,0 +1,23 @@
+
+using BeWo.Service.Plugins;
+using BS.Shared.DataContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace HausDuelken.Calculations
+{
+    public class CustomGroupDurationCalculator : GroupDurationCalculator
+    {
+		public override GroupDurationDC CalculateGroupDuration(int personCount, int employeeCount, decimal totalDuration)
+		{
+			return new GroupDurationDC()
+			{
+				SingleDuration = totalDuration / personCount * employeeCount,
+				TotalDuration = totalDuration
+			};
+		}
+	}
+}
diff --git a/ReportImp/HausDuelken/HausDuelken.csproj b/ReportImp/HausDuelken/HausDuelken.csproj
index 391351066..c891d3576 100644
--- a/ReportImp/HausDuelken/HausDuelken.csproj
+++ b/ReportImp/HausDuelken/HausDuelken.csproj
@@ -55,6 +55,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Calculations\CustomGroupDurationCalculator.cs" />
     <Compile Include="Calculations\CustomServiceRecordStatisticFactory.cs" />
     <Compile Include="CustomAuslastungBerechnung.cs" />
     <Compile Include="CustomerDataReport.cs">