diff --git a/Software/PC_Application/LibreVNA-GUI/Traces/tracexyplot.cpp b/Software/PC_Application/LibreVNA-GUI/Traces/tracexyplot.cpp
index 225fa2bf..ebe6a0c6 100644
--- a/Software/PC_Application/LibreVNA-GUI/Traces/tracexyplot.cpp
+++ b/Software/PC_Application/LibreVNA-GUI/Traces/tracexyplot.cpp
@@ -571,6 +571,19 @@ void TraceXYPlot::draw(QPainter &p)
                 auto last = traceToCoordinate(t, j-1, yAxis[i]);
                 auto now = traceToCoordinate(t, j, yAxis[i]);
 
+                // checking limits
+                for(auto limit : constantLines) {
+                    if(i == 0 && limit->getAxis() != XYPlotConstantLine::Axis::Primary) {
+                        continue;
+                    }
+                    if(i == 1 && limit->getAxis() != XYPlotConstantLine::Axis::Secondary) {
+                        continue;
+                    }
+                    if(!limit->pass(now)) {
+                        limitPassing = false;
+                    }
+                }
+
                 if(isnan(last.y()) || isnan(now.y()) || isinf(last.y()) || isinf(now.y())) {
                     continue;
                 }
@@ -595,19 +608,6 @@ void TraceXYPlot::draw(QPainter &p)
                 }
                 // draw line
                 p.drawLine(p1, p2);
-
-                // checking limits
-                for(auto limit : constantLines) {
-                    if(i == 0 && limit->getAxis() != XYPlotConstantLine::Axis::Primary) {
-                        continue;
-                    }
-                    if(i == 1 && limit->getAxis() != XYPlotConstantLine::Axis::Secondary) {
-                        continue;
-                    }
-                    if(!limit->pass(now)) {
-                        limitPassing = false;
-                    }
-                }
             }
             if(i == 0 && nPoints > 0) {
                 // only draw markers on primary YAxis and if the trace has at least one point
@@ -1352,6 +1352,13 @@ bool XYPlotConstantLine::pass(QPointF testPoint)
         // out of range, always passes
         return true;
     }
+
+    // check for inf/nan on Y value
+    if(isnan(testPoint.y()) || isinf(testPoint.y())) {
+        // can not actually evaluate the limits, use pass/fail from preferences for this case
+        return Preferences::getInstance().Graphs.limitNaNpasses;
+    }
+
     auto p = lower_bound(points.begin(), points.end(), testPoint.x(), [](QPointF p, double x) -> bool {
         return p.x() < x;
     });
diff --git a/Software/PC_Application/LibreVNA-GUI/preferences.cpp b/Software/PC_Application/LibreVNA-GUI/preferences.cpp
index 5807dad3..26561941 100644
--- a/Software/PC_Application/LibreVNA-GUI/preferences.cpp
+++ b/Software/PC_Application/LibreVNA-GUI/preferences.cpp
@@ -274,6 +274,7 @@ void PreferencesDialog::setInitialGUIState()
     ui->GraphsColorTicksBackground->setColor(p->Graphs.Color.Ticks.Background.background);
     ui->GraphsDomainChangeBehavior->setCurrentIndex((int) p->Graphs.domainChangeBehavior);
     ui->GraphsLimitIndication->setCurrentIndex((int) p->Graphs.limitIndication);
+    ui->GraphsLimitNaNpasses->setCurrentIndex(p->Graphs.limitNaNpasses ? 1 : 0);
     ui->GraphsLineWidth->setValue(p->Graphs.lineWidth);
     ui->GraphsFontSizeAxis->setValue(p->Graphs.fontSizeAxis);
     ui->GraphsFontSizeCursorOverlay->setValue(p->Graphs.fontSizeCursorOverlay);
@@ -388,6 +389,7 @@ void PreferencesDialog::updateFromGUI()
     p->Graphs.Color.Ticks.divisions = ui->GraphsColorTicksDivisions->getColor();
     p->Graphs.domainChangeBehavior = (GraphDomainChangeBehavior) ui->GraphsDomainChangeBehavior->currentIndex();
     p->Graphs.limitIndication = (GraphLimitIndication) ui->GraphsLimitIndication->currentIndex();
+    p->Graphs.limitNaNpasses = ui->GraphsLimitNaNpasses->currentIndex() == 1;
     p->Graphs.lineWidth = ui->GraphsLineWidth->value();
     p->Graphs.fontSizeAxis = ui->GraphsFontSizeAxis->value();
     p->Graphs.fontSizeCursorOverlay = ui->GraphsFontSizeCursorOverlay->value();
diff --git a/Software/PC_Application/LibreVNA-GUI/preferences.h b/Software/PC_Application/LibreVNA-GUI/preferences.h
index 08334c8d..b02042d3 100644
--- a/Software/PC_Application/LibreVNA-GUI/preferences.h
+++ b/Software/PC_Application/LibreVNA-GUI/preferences.h
@@ -129,6 +129,7 @@ class Preferences : public Savable {
         } Color;
         GraphDomainChangeBehavior domainChangeBehavior;
         GraphLimitIndication limitIndication;
+        bool limitNaNpasses;
 
         double lineWidth;
         int fontSizeAxis;
@@ -257,6 +258,7 @@ class Preferences : public Savable {
         {&Graphs.Color.Ticks.divisions, "Graphs.Color.Ticks.divisions", QColor(Qt::gray)},
         {&Graphs.domainChangeBehavior, "Graphs.domainChangeBehavior", GraphDomainChangeBehavior::AdjustGraphs},
         {&Graphs.limitIndication, "Graphs.limitIndication", GraphLimitIndication::PassFailText},
+        {&Graphs.limitNaNpasses, "Graphs.limitNaNpasses", false},
         {&Graphs.lineWidth, "Graphs.lineWidth", 1.0},
         {&Graphs.fontSizeAxis, "Graphs.fontSizeAxis", 10},
         {&Graphs.fontSizeCursorOverlay, "Graphs.fontSizeCursorOverlay", 12},
diff --git a/Software/PC_Application/LibreVNA-GUI/preferencesdialog.ui b/Software/PC_Application/LibreVNA-GUI/preferencesdialog.ui
index 3b5d3a22..30e0876b 100644
--- a/Software/PC_Application/LibreVNA-GUI/preferencesdialog.ui
+++ b/Software/PC_Application/LibreVNA-GUI/preferencesdialog.ui
@@ -98,7 +98,7 @@
        </size>
       </property>
       <property name="currentIndex">
-       <number>6</number>
+       <number>2</number>
       </property>
       <widget class="QWidget" name="Startup">
        <layout class="QHBoxLayout" name="horizontalLayout_4">
@@ -111,7 +111,7 @@
            <property name="geometry">
             <rect>
              <x>0</x>
-             <y>0</y>
+             <y>-206</y>
              <width>679</width>
              <height>836</height>
             </rect>
@@ -945,7 +945,7 @@
              <x>0</x>
              <y>-400</y>
              <width>679</width>
-             <height>964</height>
+             <height>992</height>
             </rect>
            </property>
            <layout class="QVBoxLayout" name="verticalLayout_22">
@@ -1378,7 +1378,7 @@
                </widget>
               </item>
               <item>
-               <widget class="QGroupBox" name="groupBox_17">
+               <widget class="QGroupBox" name="GraphsLimitGroup">
                 <property name="title">
                  <string>Limit checking</string>
                 </property>
@@ -1409,6 +1409,27 @@
                    </item>
                   </widget>
                  </item>
+                 <item row="1" column="0">
+                  <widget class="QLabel" name="label_62">
+                   <property name="text">
+                    <string>NaN/Inf values:</string>
+                   </property>
+                  </widget>
+                 </item>
+                 <item row="1" column="1">
+                  <widget class="QComboBox" name="GraphsLimitNaNpasses">
+                   <item>
+                    <property name="text">
+                     <string>Fail</string>
+                    </property>
+                   </item>
+                   <item>
+                    <property name="text">
+                     <string>Pass</string>
+                    </property>
+                   </item>
+                  </widget>
+                 </item>
                 </layout>
                </widget>
               </item>
@@ -1445,8 +1466,8 @@
             <rect>
              <x>0</x>
              <y>0</y>
-             <width>696</width>
-             <height>564</height>
+             <width>402</width>
+             <height>540</height>
             </rect>
            </property>
            <layout class="QVBoxLayout" name="verticalLayout_7">
@@ -1791,8 +1812,8 @@
             <rect>
              <x>0</x>
              <y>0</y>
-             <width>696</width>
-             <height>564</height>
+             <width>138</width>
+             <height>112</height>
             </rect>
            </property>
            <layout class="QHBoxLayout" name="horizontalLayout_12">