diff --git a/Modules/Core/Common/include/itkDerivativeOperator.h b/Modules/Core/Common/include/itkDerivativeOperator.h
index eb8e3602b3b..8acda0274bc 100644
--- a/Modules/Core/Common/include/itkDerivativeOperator.h
+++ b/Modules/Core/Common/include/itkDerivativeOperator.h
@@ -39,7 +39,7 @@ namespace itk
          using DerivativeOperatorType = itk::DerivativeOperator<float, 2>;
          DerivativeOperatorType derivativeOperator;
          derivativeOperator.SetDirection(0); // X dimension
-         auto radius = itk::Size<2>::Filled(1); // A radius of 1 in both dimensions is a 3x3 operator
+         constexpr auto radius = itk::Size<2>::Filled(1); // A radius of 1 in both dimensions is a 3x3 operator
          derivativeOperator.CreateToRadius(radius);
    \endcode
  * and creates a kernel that looks like:
diff --git a/Modules/Core/Common/include/itkLaplacianOperator.hxx b/Modules/Core/Common/include/itkLaplacianOperator.hxx
index 383a0a528a8..a49496fb4ab 100644
--- a/Modules/Core/Common/include/itkLaplacianOperator.hxx
+++ b/Modules/Core/Common/include/itkLaplacianOperator.hxx
@@ -70,7 +70,7 @@ LaplacianOperator<TPixel, VDimension, TAllocator>::GenerateCoefficients() -> Coe
 
   // Here we set the radius to 1's, here the
   // operator is 3x3 for 2D, 3x3x3 for 3D.
-  auto r = SizeType::Filled(1);
+  constexpr auto r = SizeType::Filled(1);
   this->SetRadius(r);
 
   // Create a vector of the correct size to hold the coefficients.
diff --git a/Modules/Core/Common/include/itkSobelOperator.h b/Modules/Core/Common/include/itkSobelOperator.h
index b2670b635a4..20cb873986b 100644
--- a/Modules/Core/Common/include/itkSobelOperator.h
+++ b/Modules/Core/Common/include/itkSobelOperator.h
@@ -35,7 +35,7 @@ namespace itk
  * 1) Set the direction by calling  \code SetDirection \endcode
  * 2) call
    \code
-   auto radius = itk::Size<2>::Filled(1);
+   constexpr auto radius = itk::Size<2>::Filled(1);
    sobelOperator.CreateToRadius(radius);
    \endcode
  * 3) You may optionally scale the coefficients of this operator using the
diff --git a/Modules/Core/ImageFunction/include/itkWindowedSincInterpolateImageFunction.h b/Modules/Core/ImageFunction/include/itkWindowedSincInterpolateImageFunction.h
index dd863f74bb7..0c0cf1ab79d 100644
--- a/Modules/Core/ImageFunction/include/itkWindowedSincInterpolateImageFunction.h
+++ b/Modules/Core/ImageFunction/include/itkWindowedSincInterpolateImageFunction.h
@@ -321,7 +321,7 @@ class ITK_TEMPLATE_EXPORT WindowedSincInterpolateImageFunction : public Interpol
   SizeType
   GetRadius() const override
   {
-    auto radius = SizeType::Filled(VRadius);
+    constexpr auto radius = SizeType::Filled(VRadius);
     return radius;
   }
 
diff --git a/Modules/Core/ImageFunction/include/itkWindowedSincInterpolateImageFunction.hxx b/Modules/Core/ImageFunction/include/itkWindowedSincInterpolateImageFunction.hxx
index cdefbe0a012..55adda7cbcf 100644
--- a/Modules/Core/ImageFunction/include/itkWindowedSincInterpolateImageFunction.hxx
+++ b/Modules/Core/ImageFunction/include/itkWindowedSincInterpolateImageFunction.hxx
@@ -64,7 +64,7 @@ WindowedSincInterpolateImageFunction<TInputImage, VRadius, TWindowFunction, TBou
   }
 
   // Set the radius for the neighborhood
-  auto radius = Size<ImageDimension>::Filled(VRadius);
+  constexpr auto radius = Size<ImageDimension>::Filled(VRadius);
 
   // Initialize the neighborhood
   IteratorType it(radius, image, image->GetBufferedRegion());
diff --git a/Modules/Core/Transform/include/itkBSplineDeformableTransform.hxx b/Modules/Core/Transform/include/itkBSplineDeformableTransform.hxx
index 9d42fa3f873..2c20b603654 100644
--- a/Modules/Core/Transform/include/itkBSplineDeformableTransform.hxx
+++ b/Modules/Core/Transform/include/itkBSplineDeformableTransform.hxx
@@ -556,7 +556,7 @@ BSplineDeformableTransform<TParametersValueType, VDimension, VSplineOrder>::Comp
   // Zero all components of jacobian
   jacobian.SetSize(SpaceDimension, this->GetNumberOfParameters());
   jacobian.Fill(0.0);
-  auto supportSize = SizeType::Filled(SplineOrder + 1);
+  constexpr auto supportSize = SizeType::Filled(SplineOrder + 1);
 
   ContinuousIndexType index =
     this->m_CoefficientImages[0]
diff --git a/Modules/Core/Transform/include/itkBSplineTransform.hxx b/Modules/Core/Transform/include/itkBSplineTransform.hxx
index 3c39fde51dc..06e97b0efff 100644
--- a/Modules/Core/Transform/include/itkBSplineTransform.hxx
+++ b/Modules/Core/Transform/include/itkBSplineTransform.hxx
@@ -52,7 +52,7 @@ BSplineTransform<TParametersValueType, VDimension, VSplineOrder>::BSplineTransfo
 
   DirectionType meshDirection;
   meshDirection.SetIdentity();
-  auto meshSize = MeshSizeType::Filled(1);
+  constexpr auto meshSize = MeshSizeType::Filled(1);
 
   this->m_FixedParameters.SetSize(VDimension * (VDimension + 3));
 
diff --git a/Modules/Filtering/Denoising/include/itkPatchBasedDenoisingImageFilter.hxx b/Modules/Filtering/Denoising/include/itkPatchBasedDenoisingImageFilter.hxx
index 215f45fde91..0c6579b0b15 100644
--- a/Modules/Filtering/Denoising/include/itkPatchBasedDenoisingImageFilter.hxx
+++ b/Modules/Filtering/Denoising/include/itkPatchBasedDenoisingImageFilter.hxx
@@ -678,7 +678,7 @@ typename PatchBasedDenoisingImageFilter<TInputImage, TOutputImage>::ThreadDataSt
   using FaceCalculatorType = typename NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImageType>;
   using FaceListType = typename FaceCalculatorType::FaceListType;
 
-  auto radius = InputImageType::SizeType::Filled(1);
+  constexpr auto radius = InputImageType::SizeType::Filled(1);
 
   if (m_NumIndependentComponents != 1)
   {
diff --git a/Modules/Filtering/DistanceMap/include/itkContourDirectedMeanDistanceImageFilter.hxx b/Modules/Filtering/DistanceMap/include/itkContourDirectedMeanDistanceImageFilter.hxx
index e457be8a284..eedc91a9eb3 100644
--- a/Modules/Filtering/DistanceMap/include/itkContourDirectedMeanDistanceImageFilter.hxx
+++ b/Modules/Filtering/DistanceMap/include/itkContourDirectedMeanDistanceImageFilter.hxx
@@ -177,7 +177,7 @@ ContourDirectedMeanDistanceImageFilter<TInputImage1, TInputImage2>::ThreadedGene
   InputImage1ConstPointer input = this->GetInput();
 
   // Find the data-set boundary "faces"
-  auto radius = SizeType::Filled(1);
+  constexpr auto radius = SizeType::Filled(1);
 
   using FaceListType = typename NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImage1Type>::FaceListType;
 
diff --git a/Modules/Filtering/FastMarching/include/itkFastMarchingImageFilterBase.hxx b/Modules/Filtering/FastMarching/include/itkFastMarchingImageFilterBase.hxx
index 90595cb8af8..b3a5fa2410e 100644
--- a/Modules/Filtering/FastMarching/include/itkFastMarchingImageFilterBase.hxx
+++ b/Modules/Filtering/FastMarching/include/itkFastMarchingImageFilterBase.hxx
@@ -53,7 +53,7 @@ FastMarchingImageFilterBase<TInput, TOutput>::FastMarchingImageFilterBase()
   m_StartIndex.Fill(0);
   m_LastIndex.Fill(0);
 
-  auto outputSize = OutputSizeType::Filled(16);
+  constexpr auto outputSize = OutputSizeType::Filled(16);
 
   NodeType outputIndex{};
 
diff --git a/Modules/Filtering/ImageFeature/include/itkCannyEdgeDetectionImageFilter.hxx b/Modules/Filtering/ImageFeature/include/itkCannyEdgeDetectionImageFilter.hxx
index 169884aeaa0..d2a07f52090 100644
--- a/Modules/Filtering/ImageFeature/include/itkCannyEdgeDetectionImageFilter.hxx
+++ b/Modules/Filtering/ImageFeature/include/itkCannyEdgeDetectionImageFilter.hxx
@@ -106,7 +106,7 @@ CannyEdgeDetectionImageFilter<TInputImage, TOutputImage>::ThreadedCompute2ndDeri
   typename OutputImageType::Pointer input = m_GaussianFilter->GetOutput();
 
   // Set iterator radius
-  auto radius = Size<ImageDimension>::Filled(1);
+  constexpr auto radius = Size<ImageDimension>::Filled(1);
 
   // Find the data-set boundary "faces"
   NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<TInputImage>                        bC;
@@ -320,7 +320,7 @@ CannyEdgeDetectionImageFilter<TInputImage, TOutputImage>::FollowEdge(IndexType
   ListNodeType * node;
 
   // Assign iterator radius
-  auto radius = Size<ImageDimension>::Filled(1);
+  constexpr auto radius = Size<ImageDimension>::Filled(1);
 
   ConstNeighborhoodIterator<TOutputImage> oit(
     radius, multiplyImageFilterOutput, multiplyImageFilterOutput->GetRequestedRegion());
@@ -395,7 +395,7 @@ CannyEdgeDetectionImageFilter<TInputImage, TOutputImage>::ThreadedCompute2ndDeri
   typename InputImageType::Pointer output = m_UpdateBuffer1;
 
   // Set iterator radius
-  auto radius = Size<ImageDimension>::Filled(1);
+  constexpr auto radius = Size<ImageDimension>::Filled(1);
 
   // Find the data-set boundary "faces"
   NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<TInputImage>                        bC;
diff --git a/Modules/Filtering/ImageFeature/include/itkMaskFeaturePointSelectionFilter.hxx b/Modules/Filtering/ImageFeature/include/itkMaskFeaturePointSelectionFilter.hxx
index 103883f0f4f..6d2ae45efaf 100644
--- a/Modules/Filtering/ImageFeature/include/itkMaskFeaturePointSelectionFilter.hxx
+++ b/Modules/Filtering/ImageFeature/include/itkMaskFeaturePointSelectionFilter.hxx
@@ -152,7 +152,7 @@ MaskFeaturePointSelectionFilter<TImage, TMask, TFeatures>::GenerateData()
   if (m_ComputeStructureTensors)
   {
     // tensor calculations access points in 2 X m_BlockRadius + 1 radius
-    auto onesSize = SizeType::Filled(1);
+    constexpr auto onesSize = SizeType::Filled(1);
     // Define the area in which tensors are going to be computed.
     const SizeType blockSize = m_BlockRadius + m_BlockRadius + onesSize;
     safeIndex += blockSize;
@@ -230,7 +230,7 @@ MaskFeaturePointSelectionFilter<TImage, TMask, TFeatures>::GenerateData()
 
         Matrix<SpacePrecisionType, ImageDimension, 1> gradI; // vector declared as column matrix
 
-        auto radius = SizeType::Filled(1); // iterate over neighbourhood of a voxel
+        constexpr auto radius = SizeType::Filled(1); // iterate over neighbourhood of a voxel
 
         RegionType center;
         center.SetSize(radius);
diff --git a/Modules/Nonunit/Review/include/itkAttributeMorphologyBaseImageFilter.hxx b/Modules/Nonunit/Review/include/itkAttributeMorphologyBaseImageFilter.hxx
index 5fec489ccc5..96a37ecb6d6 100644
--- a/Modules/Nonunit/Review/include/itkAttributeMorphologyBaseImageFilter.hxx
+++ b/Modules/Nonunit/Review/include/itkAttributeMorphologyBaseImageFilter.hxx
@@ -86,7 +86,7 @@ AttributeMorphologyBaseImageFilter<TInputImage, TOutputImage, TAttribute, TFunct
 
   SizeValueType buffsize = output->GetRequestedRegion().GetNumberOfPixels();
 
-  auto kernelRadius = SizeType::Filled(1);
+  constexpr auto kernelRadius = SizeType::Filled(1);
   using FaceCalculatorType = itk::NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<TInputImage>;
   FaceCalculatorType                        faceCalculator;
   typename FaceCalculatorType::FaceListType faceList =
diff --git a/Modules/Numerics/FEM/include/itkFEMSolver.hxx b/Modules/Numerics/FEM/include/itkFEMSolver.hxx
index 52bd0db3ad4..2d5f8e3f2b2 100644
--- a/Modules/Numerics/FEM/include/itkFEMSolver.hxx
+++ b/Modules/Numerics/FEM/include/itkFEMSolver.hxx
@@ -724,7 +724,7 @@ Solver<VDimension>::InitializeInterpolationGrid(const InterpolationGridSizeType
   // Set the interpolation grid (image) size, origin and spacing
   // from the given vectors, so that physical point of v1 is (0,0,0) and
   // physical point v2 is (size[0],size[1],size[2]).
-  auto image_size = InterpolationGridSizeType::Filled(1);
+  constexpr auto image_size = InterpolationGridSizeType::Filled(1);
   for (unsigned int i = 0; i < FEMDimension; ++i)
   {
     image_size[i] = size[i];
diff --git a/Modules/Registration/RegistrationMethodsv4/include/itkTimeVaryingBSplineVelocityFieldImageRegistrationMethod.hxx b/Modules/Registration/RegistrationMethodsv4/include/itkTimeVaryingBSplineVelocityFieldImageRegistrationMethod.hxx
index f6c6ba2758c..7a95c3ff1f6 100644
--- a/Modules/Registration/RegistrationMethodsv4/include/itkTimeVaryingBSplineVelocityFieldImageRegistrationMethod.hxx
+++ b/Modules/Registration/RegistrationMethodsv4/include/itkTimeVaryingBSplineVelocityFieldImageRegistrationMethod.hxx
@@ -299,7 +299,7 @@ TimeVaryingBSplineVelocityFieldImageRegistrationMethod<TFixedImage,
         RealType spatialNorm{};
         RealType spatioTemporalNorm{};
 
-        auto radius = TimeVaryingVelocityFieldType::SizeType::Filled(1);
+        constexpr auto radius = TimeVaryingVelocityFieldType::SizeType::Filled(1);
 
         using FaceCalculatorType = NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<TimeVaryingVelocityFieldType>;
         FaceCalculatorType                        faceCalculator;
diff --git a/Modules/Registration/RegistrationMethodsv4/include/itkTimeVaryingVelocityFieldImageRegistrationMethodv4.hxx b/Modules/Registration/RegistrationMethodsv4/include/itkTimeVaryingVelocityFieldImageRegistrationMethodv4.hxx
index 0230d005778..45f5311f422 100644
--- a/Modules/Registration/RegistrationMethodsv4/include/itkTimeVaryingVelocityFieldImageRegistrationMethodv4.hxx
+++ b/Modules/Registration/RegistrationMethodsv4/include/itkTimeVaryingVelocityFieldImageRegistrationMethodv4.hxx
@@ -362,7 +362,7 @@ TimeVaryingVelocityFieldImageRegistrationMethodv4<TFixedImage,
         RealType spatialNorm{};
         RealType spatioTemporalNorm{};
 
-        auto radius = TimeVaryingVelocityFieldType::SizeType::Filled(1);
+        constexpr auto radius = TimeVaryingVelocityFieldType::SizeType::Filled(1);
 
         using FaceCalculatorType = NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<TimeVaryingVelocityFieldType>;
         FaceCalculatorType                        faceCalculator;
diff --git a/Modules/Segmentation/ConnectedComponents/include/itkConnectedComponentFunctorImageFilter.hxx b/Modules/Segmentation/ConnectedComponents/include/itkConnectedComponentFunctorImageFilter.hxx
index 86e7045bf38..9bcfad8e3af 100644
--- a/Modules/Segmentation/ConnectedComponents/include/itkConnectedComponentFunctorImageFilter.hxx
+++ b/Modules/Segmentation/ConnectedComponents/include/itkConnectedComponentFunctorImageFilter.hxx
@@ -55,7 +55,7 @@ ConnectedComponentFunctorImageFilter<TInputImage, TOutputImage, TFunctor, TMaskI
   using InputNeighborhoodIteratorType = ConstShapedNeighborhoodIterator<TInputImage>;
   using OutputNeighborhoodIteratorType = ConstShapedNeighborhoodIterator<TOutputImage>;
 
-  auto kernelRadius = SizeType::Filled(1);
+  constexpr auto kernelRadius = SizeType::Filled(1);
 
   InputNeighborhoodIteratorType  init(kernelRadius, input, output->GetRequestedRegion());
   OutputNeighborhoodIteratorType onit(kernelRadius, output, output->GetRequestedRegion());
diff --git a/Modules/Segmentation/SuperPixel/include/itkSLICImageFilter.hxx b/Modules/Segmentation/SuperPixel/include/itkSLICImageFilter.hxx
index 499eb4b7a83..a7d3d7529d3 100644
--- a/Modules/Segmentation/SuperPixel/include/itkSLICImageFilter.hxx
+++ b/Modules/Segmentation/SuperPixel/include/itkSLICImageFilter.hxx
@@ -335,7 +335,7 @@ SLICImageFilter<TInputImage, TOutputImage, TDistancePixel>::ThreadedPerturbClust
   unsigned long stride[ImageDimension];
 
 
-  auto searchRadius = InputImageType::SizeType::Filled(1);
+  constexpr auto searchRadius = InputImageType::SizeType::Filled(1);
 
 
   using NeighborhoodType = ConstNeighborhoodIterator<TInputImage>;
diff --git a/Modules/Segmentation/Watersheds/include/itkMorphologicalWatershedFromMarkersImageFilter.hxx b/Modules/Segmentation/Watersheds/include/itkMorphologicalWatershedFromMarkersImageFilter.hxx
index 322ad2bed77..0eb0f0405dd 100644
--- a/Modules/Segmentation/Watersheds/include/itkMorphologicalWatershedFromMarkersImageFilter.hxx
+++ b/Modules/Segmentation/Watersheds/include/itkMorphologicalWatershedFromMarkersImageFilter.hxx
@@ -118,7 +118,7 @@ MorphologicalWatershedFromMarkersImageFilter<TInputImage, TLabelImage>::Generate
   MapType fah;
 
   // the radius which will be used for all the shaped iterators
-  auto radius = Size<ImageDimension>::Filled(1);
+  constexpr auto radius = Size<ImageDimension>::Filled(1);
 
   // iterator for the marker image
   using MarkerIteratorType = ConstShapedNeighborhoodIterator<LabelImageType>;