diff --git a/SourceGen/DisasmProject.cs b/SourceGen/DisasmProject.cs
index 8e59a21..b7c39b1 100644
--- a/SourceGen/DisasmProject.cs
+++ b/SourceGen/DisasmProject.cs
@@ -176,6 +176,17 @@ namespace SourceGen {
         // List of messages, mostly problems detected during analysis.
         public MessageList Messages { get; private set; }
 
+        public class CodeDataCounts {
+            public int CodeByteCount { get; set; }
+            public int DataByteCount { get; set; }
+            public int JunkByteCount { get; set; }
+
+            public void Reset() {
+                CodeByteCount = DataByteCount = JunkByteCount = 0;
+            }
+        }
+        public CodeDataCounts ByteCounts { get; private set; } = new CodeDataCounts();
+
 #if DATA_PRESCAN
         // Data scan results.
         public TypedRangeSet RepeatedBytes { get; private set; }
@@ -1409,6 +1420,9 @@ namespace SourceGen {
                 }
             }
 
+            // No particular reason to do this here, but it's convenient.
+            ByteCounts.Reset();
+
             LocalVariableLookup lvLookup = new LocalVariableLookup(LvTables, this,
                 null, false, false);
 
@@ -1518,9 +1532,18 @@ namespace SourceGen {
                 if (attr.IsDataStart) {
                     // There shouldn't be data items inside of other data items.
                     offset += attr.Length;
+
+                    if (attr.DataDescriptor != null &&
+                            attr.DataDescriptor.FormatType == FormatDescriptor.Type.Junk) {
+                        ByteCounts.JunkByteCount += attr.Length;
+                    } else {
+                        ByteCounts.DataByteCount += attr.Length;
+                    }
                 } else {
                     // Advance by one, not attr.Length, so we don't miss embedded instructions.
                     offset++;
+
+                    ByteCounts.CodeByteCount++;
                 }
             }
         }
@@ -1553,6 +1576,7 @@ namespace SourceGen {
             AutoLabel.Style style = ProjectProps.AutoLabelStyle;
             Debug.Assert(style != AutoLabel.Style.Simple);
 
+            // We don't have a list of auto labels, so just pick them out of anattribs.
             for (int offset = 0; offset < mAnattribs.Length; offset++) {
                 Anattrib attr = mAnattribs[offset];
                 if (attr.Symbol != null && attr.Symbol.SymbolSource == Symbol.Source.Auto) {
diff --git a/SourceGen/MainController.cs b/SourceGen/MainController.cs
index a70b2e9..3d92ccf 100644
--- a/SourceGen/MainController.cs
+++ b/SourceGen/MainController.cs
@@ -651,6 +651,28 @@ namespace SourceGen {
                 sb.Append(Res.Strings.TITLE_MODIFIED);
             }
             mMainWin.Title = sb.ToString();
+
+            UpdateByteCounts();
+        }
+
+        /// <summary>
+        /// Updates the code/data/junk percentages in the status bar.
+        /// </summary>
+        private void UpdateByteCounts() {
+            if (mProject == null) {
+                mMainWin.ByteCountText = string.Empty;
+                return;
+            }
+
+            Debug.Assert(mProject.ByteCounts.CodeByteCount + mProject.ByteCounts.DataByteCount +
+                mProject.ByteCounts.JunkByteCount == mProject.FileData.Length);
+
+            int total = mProject.FileData.Length;
+            float codePerc = (mProject.ByteCounts.CodeByteCount * 100.0f) / total;
+            float dataPerc = (mProject.ByteCounts.DataByteCount * 100.0f) / total;
+            float junkPerc = (mProject.ByteCounts.JunkByteCount * 100.0f) / total;
+            mMainWin.ByteCountText = string.Format(Res.Strings.STATUS_BYTE_COUNT_FMT,
+                codePerc, dataPerc, junkPerc);
         }
 
         #endregion Init and settings
diff --git a/SourceGen/Res/Strings.xaml b/SourceGen/Res/Strings.xaml
index 7077821..29719e3 100644
--- a/SourceGen/Res/Strings.xaml
+++ b/SourceGen/Res/Strings.xaml
@@ -156,6 +156,7 @@ limitations under the License.
     <system:String x:Key="str_ScanC64ScreenCode">C64 Screen Code</system:String>
     <system:String x:Key="str_SetupSystemSummaryFmt">{1} CPU @ {2} MHz</system:String>
     <system:String x:Key="str_ShowCol">Show</system:String>
+    <system:String x:Key="str_StatusByteCountFmt">{0:F1}% code, {1:F1}% data, {2:F1}% junk</system:String>
     <system:String x:Key="str_StatusReady">Ready</system:String>
     <system:String x:Key="str_StrVfyDciMixedData">DCI string has mixed data</system:String>
     <system:String x:Key="str_StrVfyDciNotTerminated">DCI string not terminated</system:String>
diff --git a/SourceGen/Res/Strings.xaml.cs b/SourceGen/Res/Strings.xaml.cs
index d121b5a..6fbbd16 100644
--- a/SourceGen/Res/Strings.xaml.cs
+++ b/SourceGen/Res/Strings.xaml.cs
@@ -293,6 +293,8 @@ namespace SourceGen.Res {
             (string)Application.Current.FindResource("str_SetupSystemSummaryFmt");
         public static string SHOW_COL =
             (string)Application.Current.FindResource("str_ShowCol");
+        public static string STATUS_BYTE_COUNT_FMT =
+            (string)Application.Current.FindResource("str_StatusByteCountFmt");
         public static string STATUS_READY =
             (string)Application.Current.FindResource("str_StatusReady");
         public static string STR_VFY_DCI_MIXED_DATA =
diff --git a/SourceGen/WpfGui/MainWindow.xaml b/SourceGen/WpfGui/MainWindow.xaml
index 8ad6e77..40ce52d 100644
--- a/SourceGen/WpfGui/MainWindow.xaml
+++ b/SourceGen/WpfGui/MainWindow.xaml
@@ -451,15 +451,21 @@ limitations under the License.
         </ToolBarTray>
 
         <StatusBar Name="mainStatusBar" DockPanel.Dock="Bottom">
-            <DockPanel LastChildFill="False"
-                       Width="{Binding ActualWidth, RelativeSource={RelativeSource FindAncestor,
-                            AncestorType={x:Type StatusBar}}}">
-                <TextBlock DockPanel.Dock="Left" Text="{Binding StatusBarText, FallbackValue=Ready}"/>
-                <Button DockPanel.Dock="Right" Margin="4,0,6,0" Padding="4,0,4,0"
+            <Grid Width="{Binding ActualWidth, RelativeSource={RelativeSource FindAncestor,
+                        AncestorType={x:Type StatusBar}}}">
+                <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="Auto"/>
+                    <ColumnDefinition Width="*"/>
+                    <ColumnDefinition Width="Auto"/>
+                </Grid.ColumnDefinitions>
+                <TextBlock Grid.Column="0" Text="{Binding StatusBarText, FallbackValue=Ready}"/>
+                <TextBlock Grid.Column="1" HorizontalAlignment="Center"
+                           Text="{Binding ByteCountText, FallbackValue=30% code; 60% data; 10% junk}"/>
+                <Button Grid.Column="2" Margin="4,0,6,0" Padding="4,0,4,0"
                         Content="{Binding MessageStatusText, FallbackValue=3 messages (1 warning/error)}"
                         Visibility="{Binding Path=CodeListVisibility}"
                         Click="MessageStatusButton_Click"/>
-            </DockPanel>
+            </Grid>
         </StatusBar>
 
         <!-- Main part of the window.  Three side-by-side panels, only the middle of which changes
diff --git a/SourceGen/WpfGui/MainWindow.xaml.cs b/SourceGen/WpfGui/MainWindow.xaml.cs
index dd64af1..8e5bb1c 100644
--- a/SourceGen/WpfGui/MainWindow.xaml.cs
+++ b/SourceGen/WpfGui/MainWindow.xaml.cs
@@ -58,6 +58,15 @@ namespace SourceGen.WpfGui {
         }
         private string mStatusBarText;
 
+        /// <summary>
+        /// Text for code/data breakdown string.
+        /// </summary>
+        public string ByteCountText {
+            get { return mByteCountText; }
+            set { mByteCountText = value; OnPropertyChanged(); }
+        }
+        private string mByteCountText;
+
         /// <summary>
         /// Width of long comment fields.
         /// </summary>