diff --git a/dev/RadioButtons/ColumnMajorUniformToLargestGridLayout.cpp b/dev/RadioButtons/ColumnMajorUniformToLargestGridLayout.cpp
index b6ae136a31..61edaee219 100644
--- a/dev/RadioButtons/ColumnMajorUniformToLargestGridLayout.cpp
+++ b/dev/RadioButtons/ColumnMajorUniformToLargestGridLayout.cpp
@@ -15,10 +15,6 @@ winrt::Size ColumnMajorUniformToLargestGridLayout::MeasureOverride(
 {
     if (auto const children = context.Children())
     {
-        auto const maxColumns = std::max(1, MaxColumns());
-        MUX_ASSERT(maxColumns > 0);
-        auto const maxItemsPerColumn = static_cast<int>(std::ceil(static_cast<double>(children.Size()) / static_cast<double>(maxColumns)));
-
         m_largestChildSize = [children, availableSize]()
         {
             auto largestChildWidth = 0.0f;
@@ -39,12 +35,11 @@ winrt::Size ColumnMajorUniformToLargestGridLayout::MeasureOverride(
             return winrt::Size(largestChildWidth, largestChildHeight);
         }();
 
-        auto const actualColumnCount = std::min(
-            static_cast<float>(maxColumns),
-            static_cast<float>(children.Size()));
+        m_actualColumnCount = CalculateColumns(children.Size(), m_largestChildSize.Width, availableSize.Width);
+        auto const maxItemsPerColumn = static_cast<int>(std::ceil(static_cast<double>(children.Size()) / static_cast<double>(m_actualColumnCount)));
         return winrt::Size(
-            (m_largestChildSize.Width * actualColumnCount) + 
-            (static_cast<float>(ColumnSpacing()) * (actualColumnCount - 1)),
+            (m_largestChildSize.Width * m_actualColumnCount) +
+            (static_cast<float>(ColumnSpacing()) * (m_actualColumnCount - 1)),
             (m_largestChildSize.Height * maxItemsPerColumn) +
             (static_cast<float>(RowSpacing()) * (maxItemsPerColumn - 1))
         );
@@ -58,11 +53,9 @@ winrt::Size ColumnMajorUniformToLargestGridLayout::ArrangeOverride(
 {
     if (auto const children = context.Children())
     {
-        auto const maxColumns = std::max(1, MaxColumns());
-        MUX_ASSERT(maxColumns > 0);
         auto const itemCount = children.Size();
-        auto const minitemsPerColumn = static_cast<int>(std::floor(static_cast<double>(itemCount) / static_cast<double>(maxColumns)));
-        auto const numberOfColumnsWithExtraElements = static_cast<int>(itemCount % maxColumns);
+        auto const minitemsPerColumn = static_cast<int>(std::floor(static_cast<float>(itemCount) / m_actualColumnCount));
+        auto const numberOfColumnsWithExtraElements = static_cast<int>(itemCount % static_cast<int>(m_actualColumnCount));
 
         auto const columnSpacing = static_cast<float>(ColumnSpacing());
         auto const rowSpacing = static_cast<float>(RowSpacing());
@@ -138,6 +131,39 @@ void ColumnMajorUniformToLargestGridLayout::OnMaxColumnsPropertyChanged(const wi
     InvalidateMeasure();
 }
 
+int ColumnMajorUniformToLargestGridLayout::CalculateColumns(int childCount, float maxItemWidth, float availableWidth)
+{
+    /*
+    --------------------------------------------------------------
+    |      |-----------|-----------| | widthNeededForExtraColumn |
+    |                                |                           |
+    |      |------|    |------|      | ColumnSpacing             |
+    | |----|      |----|      |----| | maxItemWidth              |
+    |  O RB        O RB        O RB  |                           |
+    --------------------------------------------------------------
+    */
+
+    // Every column execpt the first takes this ammount of space to fit on screen.
+    auto const widthNeededForExtraColumn = ColumnSpacing() + maxItemWidth;
+    // The number of columns from data and api ignoring available space
+    auto const requestedColumnCount = std::min(MaxColumns(), childCount);
+
+    // If columns can be added with effectively 0 extra space return as many columns as needed.
+    if (widthNeededForExtraColumn < std::numeric_limits<float>::epsilon())
+    {
+        return requestedColumnCount;
+    }
+
+    auto const extraWidthAfterFirstColumn = availableWidth - maxItemWidth;
+    auto const maxExtraColumns = std::max(0.0, std::floor(extraWidthAfterFirstColumn / widthNeededForExtraColumn));
+
+    // The smaller of number of columns from data and api and
+    // the number of columns the available space can support
+    auto const effectiveColumnCount = std::min(static_cast<double>(requestedColumnCount), maxExtraColumns + 1);
+    // return 1 even if there isn't any data
+    return std::max(1, static_cast<int>(effectiveColumnCount));
+}
+
 void ColumnMajorUniformToLargestGridLayout::ValidateGreaterThanZero(int value)
 {
     if (value <= 0)
@@ -147,7 +173,6 @@ void ColumnMajorUniformToLargestGridLayout::ValidateGreaterThanZero(int value)
 }
 
 //Testhooks helpers, only function while m_testHooksEnabled == true
-
 void ColumnMajorUniformToLargestGridLayout::SetTestHooksEnabled(bool enabled)
 {
     m_testHooksEnabled = enabled;
diff --git a/dev/RadioButtons/ColumnMajorUniformToLargestGridLayout.h b/dev/RadioButtons/ColumnMajorUniformToLargestGridLayout.h
index a92eebd7d3..78ff3ec9d3 100644
--- a/dev/RadioButtons/ColumnMajorUniformToLargestGridLayout.h
+++ b/dev/RadioButtons/ColumnMajorUniformToLargestGridLayout.h
@@ -37,6 +37,8 @@ class ColumnMajorUniformToLargestGridLayout :
     void LayoutChanged(winrt::event_token const& token);
 
 private:
+    int CalculateColumns(int childCount, float maxItemWidth, float availableWidth);
+    int m_actualColumnCount{ 1 };
     winrt::Size m_largestChildSize{ 0,0 };
 
     //Testhooks helpers, only function while m_testHooksEnabled == true
diff --git a/dev/RadioButtons/InteractionTests/RadioButtonsTestPageElements.cs b/dev/RadioButtons/InteractionTests/RadioButtonsTestPageElements.cs
index 75e7641434..dd1d392895 100644
--- a/dev/RadioButtons/InteractionTests/RadioButtonsTestPageElements.cs
+++ b/dev/RadioButtons/InteractionTests/RadioButtonsTestPageElements.cs
@@ -184,6 +184,18 @@ public ComboBox GetSourceComboBox()
         }
         private ComboBox SourceComboBox;
 
+        public Edit GetBorderWidthTextBox()
+        {
+            return GetElement(ref BorderWidthTextBox, "BorderWidthTextBox");
+        }
+        private Edit BorderWidthTextBox;
+
+        public Button GetSetBorderWidthButton()
+        {
+            return GetElement(ref SetBorderWidthButton, "SetBorderWidthButton");
+        }
+        private Button SetBorderWidthButton;
+
         public Button GetFocusSelectedItemButton()
         {
             return GetElement(ref FocusSelectedItemButton, "FocusSelectedItemButton");
diff --git a/dev/RadioButtons/InteractionTests/RadioButtonsTests.cs b/dev/RadioButtons/InteractionTests/RadioButtonsTests.cs
index 0e7debb002..b4772472ba 100644
--- a/dev/RadioButtons/InteractionTests/RadioButtonsTests.cs
+++ b/dev/RadioButtons/InteractionTests/RadioButtonsTests.cs
@@ -527,6 +527,7 @@ public void ColumnsTest()
                         SetItemType(type);
                         SetNumberOfColumns(1);
                         SetNumberOfItems(10);
+                        SetBorderWidthToInf();
 
                         VerifyLayoutData(10, 1, 0);
                         SetNumberOfColumns(3);
@@ -538,10 +539,21 @@ public void ColumnsTest()
                         SetNumberOfColumns(10);
                         VerifyLayoutData(1, 10, 0);
                         SetNumberOfColumns(20);
-                        VerifyLayoutData(0, 10, 10);
+                        VerifyLayoutData(1, 10, 0);
 
                         SetNumberOfItems(77);
                         VerifyLayoutData(3, 20, 17);
+
+                        SetBorderWidth(100);
+                        VerifyLayoutData(77, 1, 0);
+                        SetBorderWidth(200);
+                        VerifyLayoutData(77, 1, 0);
+                        SetBorderWidth(300);
+                        VerifyLayoutData(38, 2, 1);
+                        SetBorderWidth(500);
+                        VerifyLayoutData(25, 3, 2);
+                        SetBorderWidth(550);
+                        VerifyLayoutData(19, 4, 1);
                     }
                 }
             }
@@ -651,6 +663,18 @@ void SetNumberOfItems(int items)
             elements.GetSetNumberOfItemsButton().Click();
         }
 
+        void SetBorderWidth(float width)
+        {
+            elements.GetBorderWidthTextBox().SetValue(width.ToString());
+            elements.GetSetBorderWidthButton().Click();
+        }
+
+        void SetBorderWidthToInf()
+        {
+            elements.GetBorderWidthTextBox().SetValue("inf");
+            elements.GetSetBorderWidthButton().Click();
+        }
+
         void SetSource(RadioButtonsSourceLocation location)
         {
             switch(location)
diff --git a/dev/RadioButtons/TestUI/RadioButtonsPage.xaml b/dev/RadioButtons/TestUI/RadioButtonsPage.xaml
index 19a3150690..26c28966bb 100644
--- a/dev/RadioButtons/TestUI/RadioButtonsPage.xaml
+++ b/dev/RadioButtons/TestUI/RadioButtonsPage.xaml
@@ -22,7 +22,9 @@
             <Grid Grid.Column="0" Margin="5" MinWidth="500" MaxWidth="800">
                 <ScrollViewer HorizontalScrollMode="Enabled" HorizontalScrollBarVisibility="Visible">
                     <StackPanel>
-                        <controls:RadioButtons x:Name="TestRadioButtons" AutomationProperties.Name="TestRadioButtons" Header="I'm the header" SelectionChanged="TestRadioButtons_SelectionChanged" GotFocus="TestRadioButtons_GotFocus" LostFocus="TestRadioButtons_LostFocus"/>
+                        <Border x:Name="TestRadioButtonsBorder" BorderBrush="Black" BorderThickness="1">
+                            <controls:RadioButtons x:Name="TestRadioButtons" AutomationProperties.Name="TestRadioButtons" Header="I'm the header" SelectionChanged="TestRadioButtons_SelectionChanged" GotFocus="TestRadioButtons_GotFocus" LostFocus="TestRadioButtons_LostFocus"/>
+                        </Border>
                         <controls:RadioButtons x:Name="SecondTestRadioButton" Header="A Second Radio Buttons, 0 selected">
                             <RadioButton x:Name="TheRadioButton">"I'm really a Radio Button"</RadioButton>
                             <x:String>I'm just a string</x:String>
@@ -68,6 +70,7 @@
                                 <RowDefinition Height="Auto"/>
                                 <!--20-->
                                 <RowDefinition Height="Auto"/>
+                                <RowDefinition Height="Auto"/>
                             </Grid.RowDefinitions>
                             <Grid.ColumnDefinitions>
                                 <ColumnDefinition Width="*"/>
@@ -111,9 +114,11 @@
                             <TextBlock Text="Checked:" HorizontalAlignment="Right" VerticalAlignment="Center" Grid.Row="16" Grid.Column="0"/>
                             <CheckBox x:Name="CustomCheckedCheckBox" AutomationProperties.Name="CustomCheckedCheckBox" HorizontalAlignment="Left" Grid.Row="16" Grid.Column="1"/>
                             <TextBlock Text="TestPage Utilities" HorizontalAlignment="Center" Foreground="Red" Grid.Row="17" Grid.Column="0" Grid.ColumnSpan="2"/>
-                            <Button Content="Focus Selected Item" AutomationProperties.Name="FocusSelectedItemButton" Grid.Row="18" Grid.Column="0" Grid.ColumnSpan="2" Click="FocusSelectedItemButton_Clicked"/>
-                            <Button Content="Select 5 then change source" AutomationProperties.Name="Select5ThenChangeSourceButton" Grid.Row="19" Grid.Column="0" Grid.ColumnSpan="2" Click="Select5ThenChangeSourceButton_Clicked"/>
-                            <CheckBox x:Name="AllowInvalidValuesCheckBox" AutomationProperties.Name="AllowInvalidValuesCheckBox" Content="Allow Invalid Values" HorizontalAlignment="Center" IsChecked="False" IsEnabled="False" Grid.Row="20" Grid.Column="0" Grid.ColumnSpan="2" />
+                            <TextBox x:Name="BorderWidthTextBox" AutomationProperties.Name="BorderWidthTextBox" Text="inf" Grid.Row="18" Grid.Column="0" HorizontalAlignment="Right"/>
+                            <Button x:Name="SetBorderWidthButton" AutomationProperties.Name="SetBorderWidthButton" Content="Set" Grid.Row="18" Grid.Column="1" HorizontalAlignment="Left" Click="SetBorderWidthButton_Click"/>
+                            <Button Content="Focus Selected Item" AutomationProperties.Name="FocusSelectedItemButton" Grid.Row="19" Grid.Column="0" Grid.ColumnSpan="2" Click="FocusSelectedItemButton_Clicked"/>
+                            <Button Content="Select 5 then change source" AutomationProperties.Name="Select5ThenChangeSourceButton" Grid.Row="20" Grid.Column="0" Grid.ColumnSpan="2" Click="Select5ThenChangeSourceButton_Clicked"/>
+                            <CheckBox x:Name="AllowInvalidValuesCheckBox" AutomationProperties.Name="AllowInvalidValuesCheckBox" Content="Allow Invalid Values" HorizontalAlignment="Center" IsChecked="False" IsEnabled="False" Grid.Row="21" Grid.Column="0" Grid.ColumnSpan="2" />
                         </Grid>
                     </ScrollViewer>
                     <ScrollViewer Margin="5">
diff --git a/dev/RadioButtons/TestUI/RadioButtonsPage.xaml.cs b/dev/RadioButtons/TestUI/RadioButtonsPage.xaml.cs
index ceca9ba476..a64bdb1f87 100644
--- a/dev/RadioButtons/TestUI/RadioButtonsPage.xaml.cs
+++ b/dev/RadioButtons/TestUI/RadioButtonsPage.xaml.cs
@@ -242,6 +242,27 @@ private void FocusSelectedItemButton_Clicked(object sender, RoutedEventArgs e)
             ((Control)repeater.TryGetElement(TestRadioButtons.SelectedIndex)).Focus(FocusState.Keyboard);
         }
 
+        private void SetBorderWidthButton_Click(object sender, RoutedEventArgs e)
+        {
+            if(this.BorderWidthTextBox.Text == "inf")
+            {
+                this.TestRadioButtonsBorder.Width = float.NaN;
+                this.BorderWidthTextBox.BorderBrush = new SolidColorBrush(Colors.Black);
+            }
+            else
+            {
+                if(float.TryParse(this.BorderWidthTextBox.Text, out float value))
+                {
+                    this.TestRadioButtonsBorder.Width = value;
+                    this.BorderWidthTextBox.BorderBrush = new SolidColorBrush(Colors.Black);
+                }
+                else
+                {
+                    this.BorderWidthTextBox.BorderBrush = new SolidColorBrush(Colors.DarkRed);
+                }
+            }
+        }
+
         private void Select5ThenChangeSourceButton_Clicked(object sender, RoutedEventArgs e)
         {
             TestRadioButtons.SelectedIndex = 5;