diff --git a/MatterControl.Printing/GCode/GCodeFile.cs b/MatterControl.Printing/GCode/GCodeFile.cs
index 066272677..c3c81ac6a 100644
--- a/MatterControl.Printing/GCode/GCodeFile.cs
+++ b/MatterControl.Printing/GCode/GCodeFile.cs
@@ -72,7 +72,7 @@ namespace MatterControl.Printing
 
 		public abstract double GetLayerHeight(int layerIndex);
 
-		public abstract double GetLayerZOffset(int layerIndex);
+		public abstract double GetLayerTop(int layerIndex);
 
 		public abstract int GetLayerIndex(int instructionIndex);
 
diff --git a/MatterControl.Printing/GCode/GCodeFileStreamed.cs b/MatterControl.Printing/GCode/GCodeFileStreamed.cs
index d19dbd151..7ed824aed 100644
--- a/MatterControl.Printing/GCode/GCodeFileStreamed.cs
+++ b/MatterControl.Printing/GCode/GCodeFileStreamed.cs
@@ -149,7 +149,7 @@ namespace MatterControl.Printing
 			throw new NotImplementedException();
 		}
 
-		public override double GetLayerZOffset(int layerIndex)
+		public override double GetLayerTop(int layerIndex)
 		{
 			throw new NotImplementedException();
 		}
diff --git a/MatterControl.Printing/GCode/GCodeMemoryFile.cs b/MatterControl.Printing/GCode/GCodeMemoryFile.cs
index 94e2f5963..8b329aec4 100644
--- a/MatterControl.Printing/GCode/GCodeMemoryFile.cs
+++ b/MatterControl.Printing/GCode/GCodeMemoryFile.cs
@@ -927,10 +927,10 @@ namespace MatterControl.Printing
 			return .5;
 		}
 
-		public override double GetLayerZOffset(int layerIndex)
+		public override double GetLayerTop(int layerIndex)
 		{
 			double total = 0;
-			for (int i = 0; i < layerIndex; i++)
+			for (int i = 0; i <= layerIndex; i++)
 			{
 				total += GetLayerHeight(i);
 			}
diff --git a/PartPreviewWindow/GCodeDetails/GCodeDetails.cs b/PartPreviewWindow/GCodeDetails/GCodeDetails.cs
index cee3559c2..2dabc0e08 100644
--- a/PartPreviewWindow/GCodeDetails/GCodeDetails.cs
+++ b/PartPreviewWindow/GCodeDetails/GCodeDetails.cs
@@ -103,9 +103,9 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 			return loadedGCode.GetLayerHeight(layerIndex);
 		}
 
-		internal object GetLayerZOffset(int layerIndex)
+		internal object GetLayerTop(int layerIndex)
 		{
-			return loadedGCode.GetLayerZOffset(layerIndex);
+			return loadedGCode.GetLayerTop(layerIndex);
 		}
 
 		public string LayerTime(int activeLayerIndex)
diff --git a/PartPreviewWindow/GCodeDetails/GCodeLayerDetailsView.cs b/PartPreviewWindow/GCodeDetails/GCodeLayerDetailsView.cs
index a84534ac9..344311d49 100644
--- a/PartPreviewWindow/GCodeDetails/GCodeLayerDetailsView.cs
+++ b/PartPreviewWindow/GCodeDetails/GCodeLayerDetailsView.cs
@@ -81,14 +81,14 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 
 			GuiWidget layerTime = AddSetting("Time".Localize(), "", this);
 			GuiWidget layerHeight = AddSetting("Height".Localize(), "", this);
-			GuiWidget layerWidth = AddSetting("Z Offset".Localize(), "", this);
+			GuiWidget layerWidth = AddSetting("Layer Top".Localize(), "", this);
 			GuiWidget layerFanSpeeds = AddSetting("Fan Speed".Localize(), "", this);
 
 			void UpdateLayerDisplay(object sender, EventArgs e)
 			{
 				layerTime.Text = gcodeDetails.LayerTime(sceneContext.ActiveLayerIndex);
 				layerHeight.Text = $"{gcodeDetails.GetLayerHeight(sceneContext.ActiveLayerIndex):0.###}";
-				layerWidth.Text = $"{gcodeDetails.GetLayerZOffset(sceneContext.ActiveLayerIndex):0.###}";
+				layerWidth.Text = $"{gcodeDetails.GetLayerTop(sceneContext.ActiveLayerIndex):0.###}";
 				var fanSpeed = gcodeDetails.GetLayerFanSpeeds(sceneContext.ActiveLayerIndex);
 				layerFanSpeeds.Text = string.IsNullOrWhiteSpace(fanSpeed) ? "Unchanged" : fanSpeed;
 			}