diff --git a/src/Mod/Part/App/PrimitiveFeature.cpp b/src/Mod/Part/App/PrimitiveFeature.cpp
index b6edd74973..d77265d5aa 100644
--- a/src/Mod/Part/App/PrimitiveFeature.cpp
+++ b/src/Mod/Part/App/PrimitiveFeature.cpp
@@ -29,6 +29,7 @@
 # include <BRepBuilderAPI_MakeVertex.hxx>
 # include <BRepBuilderAPI_MakeSolid.hxx>
 # include <BRepBuilderAPI_MakePolygon.hxx>
+# include <BRepGProp.hxx>
 # include <BRepPrim_Cylinder.hxx>
 # include <BRepPrim_Wedge.hxx>
 # include <BRepPrimAPI_MakeCone.hxx>
@@ -746,6 +747,8 @@ Helix::Helix()
     LocalCoord.setEnums(LocalCSEnums);
     ADD_PROPERTY_TYPE(Style,(long(0)),"Helix style",App::Prop_Hidden,"Old style creates incorrect and new style create correct helices");
     Style.setEnums(StyleEnums);
+    ADD_PROPERTY_TYPE(Length,(1.0),"Helix",App::Prop_None,"The length of the helix");
+    Length.setReadOnly(true);
 }
 
 void Helix::onChanged(const App::Property* prop)
@@ -799,6 +802,12 @@ App::DocumentObjectExecReturn *Helix::execute()
         Standard_Real myRadiusTop = myRadius + myHeight * tan(myAngle/180.0f*M_PI);
 
         this->Shape.setValue(TopoShape().makeSpiralHelix(myRadius, myRadiusTop, myHeight, nbTurns, mySegLen, myLocalCS));
+        // props.Mass() may seem a strange way to get the Length, but 
+        // https://dev.opencascade.org/doc/refman/html/class_b_rep_g_prop.html#ab1d4bacc290bfaa8df13dd99ae7b8e70
+        // confirms this.
+        GProp_GProps props;
+        BRepGProp::LinearProperties(Shape.getShape().getShape(), props);
+        Length.setValue(props.Mass());
     }
     catch (Standard_Failure& e) {
 
@@ -820,6 +829,8 @@ Spiral::Spiral()
     Rotations.setConstraints(&quantityRange);
     ADD_PROPERTY_TYPE(SegmentLength,(1.0),"Spiral",App::Prop_None,"The number of turns per spiral subdivision");
     SegmentLength.setConstraints(&quantityRange);
+    ADD_PROPERTY_TYPE(Length,(1.0),"Spiral",App::Prop_None,"The length of the spiral");
+    Length.setReadOnly(true);
 }
 
 void Spiral::onChanged(const App::Property* prop)
@@ -862,6 +873,9 @@ App::DocumentObjectExecReturn *Spiral::execute()
             Standard_Failure::Raise("Number of rotations too small");
 
         this->Shape.setValue(TopoShape().makeSpiralHelix(myRadius, myRadiusTop, 0, myNumRot, mySegLen, Standard_False));
+        GProp_GProps props;
+        BRepGProp::LinearProperties(Shape.getShape().getShape(), props);
+        Length.setValue(props.Mass());
         return Primitive::execute();
     }
     catch (Standard_Failure& e) {
diff --git a/src/Mod/Part/App/PrimitiveFeature.h b/src/Mod/Part/App/PrimitiveFeature.h
index 33c6b5a3a6..ad4ba509c4 100644
--- a/src/Mod/Part/App/PrimitiveFeature.h
+++ b/src/Mod/Part/App/PrimitiveFeature.h
@@ -314,6 +314,7 @@ public:
     App::PropertyQuantityConstraint SegmentLength;
     App::PropertyEnumeration     LocalCoord;
     App::PropertyEnumeration     Style;
+    App::PropertyLength Length;
 
     /** @name methods override feature */
     //@{
@@ -345,6 +346,7 @@ public:
     App::PropertyQuantityConstraint Rotations;
     App::PropertyLength Radius;
     App::PropertyQuantityConstraint SegmentLength;
+    App::PropertyLength Length;
 
     /** @name methods override feature */
     //@{