diff --git a/corrscope/corrscope.py b/corrscope/corrscope.py
index 8205dca..a8f5d5c 100644
--- a/corrscope/corrscope.py
+++ b/corrscope/corrscope.py
@@ -90,7 +90,7 @@ class Config(
 
     master_audio: Optional[str]
     begin_time: float = with_units("s", default=0)
-    end_time: Optional[float] = None
+    end_time: Optional[float] = with_units("s", default=None)
 
     fps: int
 
diff --git a/corrscope/gui/model_bind.py b/corrscope/gui/model_bind.py
index 9ad952f..342013f 100644
--- a/corrscope/gui/model_bind.py
+++ b/corrscope/gui/model_bind.py
@@ -278,6 +278,26 @@ class BoundDoubleSpinBox(qw.QDoubleSpinBox, BoundWidget):
     set_model = model_setter(float)
 
 
+class BoundDoubleOrNone(qw.QDoubleSpinBox, BoundWidget):
+    bind_widget = BoundSpinBox.bind_widget
+
+    def set_gui(self, value):
+        self.setValue(value or 0.0)
+
+    gui_changed = alias("valueChanged")
+
+    @Slot(float)
+    def set_model(self: BoundWidget, value: float):
+        value = value or None
+        try:
+            self.pmodel[self.path] = value
+        except CorrError:
+            self.setPalette(self.error_palette)
+        else:
+            BoundWidget.set_model(self, value)
+            self.setPalette(self.default_palette)
+
+
 # CheckState inherits from int on PyQt5 and Enum on PyQt6. To compare integers with
 # CheckState on both PyQt5 and 6, we have to call CheckState(int).
 CheckState = qc.Qt.CheckState
diff --git a/corrscope/gui/view_mainwindow.py b/corrscope/gui/view_mainwindow.py
index 307018e..86436b3 100644
--- a/corrscope/gui/view_mainwindow.py
+++ b/corrscope/gui/view_mainwindow.py
@@ -115,8 +115,18 @@ class MainWindow(QWidget):
                 with add_row(s, "", BoundDoubleSpinBox) as self.amplification:
                     self.amplification.setSingleStep(0.1)
 
-                with add_row(s, "", BoundDoubleSpinBox) as self.begin_time:
-                    self.begin_time.setMaximum(9999.0)
+                with add_row(s, tr("Time"), QHBoxLayout) as self.layout_time:
+                    with append_widget(s, BoundDoubleSpinBox) as self.begin_time:
+                        self.begin_time.setMaximum(9999.0)
+                        self.begin_time.setDecimals(1)
+
+                    with append_widget(s, QLabel) as dash:
+                        dash.setText(tr("–"))
+
+                    with append_widget(s, BoundDoubleOrNone) as self.end_time:
+                        self.end_time.setMaximum(9999.0)
+                        self.end_time.setDecimals(1)
+                        self.end_time.setSpecialValueText(NBSP)
 
             with append_widget(
                 s, QGroupBox, title=tr("Performance (Preview Only)"), layout=QFormLayout
@@ -535,7 +545,6 @@ class MainWindow(QWidget):
         self.trigger_msL.setText(tr("Trigger Width"))
         self.render_msL.setText(tr("Render Width"))
         self.amplificationL.setText(tr("Amplification"))
-        self.begin_timeL.setText(tr("Begin Time"))
         self.render_resolutionL.setText(tr("Resolution"))
         self.render__bg_colorL.setText(tr("Background"))
         self.render__init_line_colorL.setText(tr("Line Color"))
@@ -582,6 +591,7 @@ from corrscope.gui.model_bind import (
     BoundColorWidget,
     OptionalColorWidget,
     BoundFontButton,
+    BoundDoubleOrNone,
 )
 
 # Delete unbound widgets, so they cannot accidentally be used.