Index: Ringtoets/Common/src/Ringtoets.Common.Data/Calculation/ICalculation.cs
===================================================================
diff -u -re69c7f4997137a5b3ea5593501f96c1428bbbf13 -r73fa8b14820af5ffd04e2e428a32c95426c36553
--- Ringtoets/Common/src/Ringtoets.Common.Data/Calculation/ICalculation.cs	(.../ICalculation.cs)	(revision e69c7f4997137a5b3ea5593501f96c1428bbbf13)
+++ Ringtoets/Common/src/Ringtoets.Common.Data/Calculation/ICalculation.cs	(.../ICalculation.cs)	(revision 73fa8b14820af5ffd04e2e428a32c95426c36553)
@@ -24,7 +24,7 @@
     /// <summary>
     /// A calculation related object.
     /// </summary>
-    public interface ICalculation : ICalculatable, ICalculationBase
+    public interface ICalculation : ICalculationBase, ICalculatable
     {
         /// <summary>
         /// Gets a value indicating whether or not this calculation item contains calculation output.
Index: Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Data/GrassCoverErosionOutwardsWaveConditionsCalculation.cs
===================================================================
diff -u -re8d938b175e6d5ad1f878991aff8b6d1266386aa -r73fa8b14820af5ffd04e2e428a32c95426c36553
--- Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Data/GrassCoverErosionOutwardsWaveConditionsCalculation.cs	(.../GrassCoverErosionOutwardsWaveConditionsCalculation.cs)	(revision e8d938b175e6d5ad1f878991aff8b6d1266386aa)
+++ Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Data/GrassCoverErosionOutwardsWaveConditionsCalculation.cs	(.../GrassCoverErosionOutwardsWaveConditionsCalculation.cs)	(revision 73fa8b14820af5ffd04e2e428a32c95426c36553)
@@ -51,7 +51,13 @@
 
         public string Name { get; set; }
 
-        public Comment Comments { get; private set; }
+        public bool ShouldCalculate
+        {
+            get
+            {
+                return !HasOutput;
+            }
+        }
 
         public bool HasOutput
         {
@@ -61,6 +67,8 @@
             }
         }
 
+        public Comment Comments { get; private set; }
+
         public void ClearOutput()
         {
             Output = null;
Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsCalculation.cs
===================================================================
diff -u -r6df492af2166d167f1a154b7997c85a4118b1759 -r73fa8b14820af5ffd04e2e428a32c95426c36553
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsCalculation.cs	(.../MacroStabilityInwardsCalculation.cs)	(revision 6df492af2166d167f1a154b7997c85a4118b1759)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsCalculation.cs	(.../MacroStabilityInwardsCalculation.cs)	(revision 73fa8b14820af5ffd04e2e428a32c95426c36553)
@@ -53,6 +53,14 @@
 
         public string Name { get; set; }
 
+        public bool ShouldCalculate
+        {
+            get
+            {
+                return !HasOutput;
+            }
+        }
+
         public bool HasOutput
         {
             get
Index: Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingCalculation.cs
===================================================================
diff -u -r6df492af2166d167f1a154b7997c85a4118b1759 -r73fa8b14820af5ffd04e2e428a32c95426c36553
--- Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingCalculation.cs	(.../PipingCalculation.cs)	(revision 6df492af2166d167f1a154b7997c85a4118b1759)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingCalculation.cs	(.../PipingCalculation.cs)	(revision 73fa8b14820af5ffd04e2e428a32c95426c36553)
@@ -57,6 +57,14 @@
 
         public string Name { get; set; }
 
+        public bool ShouldCalculate
+        {
+            get
+            {
+                return !HasOutput;
+            }
+        }
+
         public bool HasOutput
         {
             get
Index: Ringtoets/StabilityStoneCover/src/Ringtoets.StabilityStoneCover.Data/StabilityStoneCoverWaveConditionsCalculation.cs
===================================================================
diff -u -re8d938b175e6d5ad1f878991aff8b6d1266386aa -r73fa8b14820af5ffd04e2e428a32c95426c36553
--- Ringtoets/StabilityStoneCover/src/Ringtoets.StabilityStoneCover.Data/StabilityStoneCoverWaveConditionsCalculation.cs	(.../StabilityStoneCoverWaveConditionsCalculation.cs)	(revision e8d938b175e6d5ad1f878991aff8b6d1266386aa)
+++ Ringtoets/StabilityStoneCover/src/Ringtoets.StabilityStoneCover.Data/StabilityStoneCoverWaveConditionsCalculation.cs	(.../StabilityStoneCoverWaveConditionsCalculation.cs)	(revision 73fa8b14820af5ffd04e2e428a32c95426c36553)
@@ -51,7 +51,13 @@
 
         public string Name { get; set; }
 
-        public Comment Comments { get; private set; }
+        public bool ShouldCalculate
+        {
+            get
+            {
+                return !HasOutput;
+            }
+        }
 
         public bool HasOutput
         {
@@ -61,6 +67,8 @@
             }
         }
 
+        public Comment Comments { get; private set; }
+
         public void ClearOutput()
         {
             Output = null;
Index: Ringtoets/WaveImpactAsphaltCover/src/Ringtoets.WaveImpactAsphaltCover.Data/WaveImpactAsphaltCoverWaveConditionsCalculation.cs
===================================================================
diff -u -re8d938b175e6d5ad1f878991aff8b6d1266386aa -r73fa8b14820af5ffd04e2e428a32c95426c36553
--- Ringtoets/WaveImpactAsphaltCover/src/Ringtoets.WaveImpactAsphaltCover.Data/WaveImpactAsphaltCoverWaveConditionsCalculation.cs	(.../WaveImpactAsphaltCoverWaveConditionsCalculation.cs)	(revision e8d938b175e6d5ad1f878991aff8b6d1266386aa)
+++ Ringtoets/WaveImpactAsphaltCover/src/Ringtoets.WaveImpactAsphaltCover.Data/WaveImpactAsphaltCoverWaveConditionsCalculation.cs	(.../WaveImpactAsphaltCoverWaveConditionsCalculation.cs)	(revision 73fa8b14820af5ffd04e2e428a32c95426c36553)
@@ -51,7 +51,13 @@
 
         public string Name { get; set; }
 
-        public Comment Comments { get; private set; }
+        public bool ShouldCalculate
+        {
+            get
+            {
+                return !HasOutput;
+            }
+        }
 
         public bool HasOutput
         {
@@ -61,6 +67,8 @@
             }
         }
 
+        public Comment Comments { get; private set; }
+
         public void ClearOutput()
         {
             Output = null;