diff --git a/qupulse/pulses/mapping_pulse_template.py b/qupulse/pulses/mapping_pulse_template.py
index 824a60e62..a9ff5a0f1 100644
--- a/qupulse/pulses/mapping_pulse_template.py
+++ b/qupulse/pulses/mapping_pulse_template.py
@@ -201,7 +201,10 @@ def defined_channels(self) -> Set[ChannelID]:
 
     @property
     def duration(self) -> Expression:
-        return self.__template.duration.evaluate_symbolic(self.__parameter_mapping)
+        return self.__template.duration.evaluate_symbolic(
+            {parameter_name: expression.underlying_expression
+             for parameter_name, expression in self.__parameter_mapping.items()}
+        )
 
     def get_serialization_data(self, serializer: Optional[Serializer]=None) -> Dict[str, Any]:
         data = super().get_serialization_data(serializer)
diff --git a/tests/pulses/mapping_pulse_template_tests.py b/tests/pulses/mapping_pulse_template_tests.py
index 6248a391b..2a70c78da 100644
--- a/tests/pulses/mapping_pulse_template_tests.py
+++ b/tests/pulses/mapping_pulse_template_tests.py
@@ -253,6 +253,15 @@ def test_integral(self) -> None:
 
         self.assertEqual({'a': Expression('2*f'), 'B': Expression('-3.2*f+2.3')}, pulse.integral)
 
+    def test_duration(self):
+        seconds2ns = 1e9
+        pulse_duration = 1.0765001496284785e-07
+
+        dpt = DummyPulseTemplate(duration=Expression('duration'), parameter_names={'duration'},
+                                   defined_channels={'A'})
+        mpt = MappingPulseTemplate(dpt, parameter_mapping={'duration': seconds2ns * pulse_duration})
+        self.assertEqual(seconds2ns * pulse_duration, mpt.duration)
+
     def test_drop_channel(self):
         dummy = DummyPulseTemplate(defined_channels={'A', 'B', 'C', 'D'},
                                    parameter_names={'k', 'f', 'b'})