diff --git a/flatcamEditors/FlatCAMGeoEditor.py b/flatcamEditors/FlatCAMGeoEditor.py
index c50d91d8..3c206ae4 100644
--- a/flatcamEditors/FlatCAMGeoEditor.py
+++ b/flatcamEditors/FlatCAMGeoEditor.py
@@ -437,7 +437,7 @@ class PaintOptionsTool(FlatCAMTool):
         grid.addWidget(self.painttooldia_entry, 0, 1)
 
         # Overlap
-        ovlabel = QtWidgets.QLabel(_('Overlap:'))
+        ovlabel = QtWidgets.QLabel(_('Overlap Rate:'))
         ovlabel.setToolTip(
             _("How much (fraction) of the tool width to overlap each tool pass.\n"
             "Example:\n"
diff --git a/flatcamGUI/FlatCAMGUI.py b/flatcamGUI/FlatCAMGUI.py
index 9e1357e4..e6c92393 100644
--- a/flatcamGUI/FlatCAMGUI.py
+++ b/flatcamGUI/FlatCAMGUI.py
@@ -4865,7 +4865,7 @@ class ToolsNCCPrefGroupUI(OptionsGroupUI):
         self.ncc_tool_dia_entry = FCEntry()
         grid0.addWidget(self.ncc_tool_dia_entry, 0, 1)
 
-        nccoverlabel = QtWidgets.QLabel(_('Overlap:'))
+        nccoverlabel = QtWidgets.QLabel(_('Overlap Rate:'))
         nccoverlabel.setToolTip(
            _( "How much (fraction) of the tool width to overlap each tool pass.\n"
             "Example:\n"
@@ -5110,7 +5110,7 @@ class ToolsPaintPrefGroupUI(OptionsGroupUI):
         grid0.addWidget(self.painttooldia_entry, 0, 1)
 
         # Overlap
-        ovlabel = QtWidgets.QLabel(_('Overlap:'))
+        ovlabel = QtWidgets.QLabel(_('Overlap Rate:'))
         ovlabel.setToolTip(
             _("How much (fraction) of the tool\n"
             "width to overlap each tool pass.")
diff --git a/flatcamTools/ToolNonCopperClear.py b/flatcamTools/ToolNonCopperClear.py
index aab53abc..4b7ee0de 100644
--- a/flatcamTools/ToolNonCopperClear.py
+++ b/flatcamTools/ToolNonCopperClear.py
@@ -162,7 +162,7 @@ class NonCopperClear(FlatCAMTool, Gerber):
         e_lab_1 = QtWidgets.QLabel('')
         grid3.addWidget(e_lab_1, 0, 0)
 
-        nccoverlabel = QtWidgets.QLabel(_('Overlap:'))
+        nccoverlabel = QtWidgets.QLabel(_('Overlap Rate:'))
         nccoverlabel.setToolTip(
             _("How much (fraction) of the tool width to overlap each tool pass.\n"
             "Example:\n"
@@ -628,6 +628,11 @@ class NonCopperClear(FlatCAMTool, Gerber):
                 return
         over = over if over else self.app.defaults["tools_nccoverlap"]
 
+        if over >= 1 or over < 0:
+            self.app.inform.emit(_("[ERROR_NOTCL] Overlap value must be between "
+                                  "0 (inclusive) and 1 (exclusive), "))
+            return
+
         try:
             margin = float(self.ncc_margin_entry.get_value())
         except ValueError: