diff --git a/src/damaris/gui/DamarisGUI.py b/src/damaris/gui/DamarisGUI.py
index 2c1896d..42cee90 100644
--- a/src/damaris/gui/DamarisGUI.py
+++ b/src/damaris/gui/DamarisGUI.py
@@ -210,6 +210,7 @@ class DamarisGUI:
 
         #connect event handlers
         eventhandlers = {"on_toolbar_run_button_clicked": self.start_experiment,
+                        "on_toolbar_estimate_button_clicked": self.estimate_duration,
                         "on_toolbar_pause_button_toggled": self.pause_experiment,
                         "on_toolbar_stop_button_clicked": self.stop_experiment,
                         "on_doc_menu_activate": self.show_doc_menu,
@@ -389,6 +390,117 @@ class DamarisGUI:
 
     # toolbar related events:
 
+    def estimate_duration( self, widget, data=None ):
+        """
+        Estimate the total experiment duration and show a dialog.
+        """
+        from datetime import datetime, timedelta
+        from damaris.experiments.DurationEstimator import estimate_duration
+
+        exp_script, _ = self.sw.get_scripts()
+
+        # validate syntax first
+        try:
+            compile(exp_script, "Experiment Script", "exec")
+        except SyntaxError as e:
+            ln = e.lineno if isinstance(e.lineno, int) else 0
+            lo = e.offset if isinstance(e.offset, int) else 0
+            msg = "Experiment Script: %s at line %d, col %d" % (e.__class__.__name__, ln, lo)
+            dialog = gtk.MessageDialog(
+                parent=self.main_window,
+                flags=gtk.DialogFlags.MODAL,
+                type=gtk.MessageType.ERROR,
+                buttons=gtk.ButtonsType.OK,
+                message_format=msg
+            )
+            dialog.run()
+            dialog.destroy()
+            return
+
+        # run estimator in a background thread to not freeze the GUI
+        dialog = gtk.MessageDialog(
+            parent=self.main_window,
+            flags=gtk.DialogFlags.MODAL,
+            type=gtk.MessageType.INFO,
+            buttons=gtk.ButtonsType.CLOSE,
+            message_format="Estimating duration..."
+        )
+        dialog.set_resizable(False)
+        dialog.show()
+
+        result = [None]
+        error = [None]
+        done = threading.Event()
+
+        def run_estimate():
+            try:
+                result[0] = estimate_duration(exp_script)
+            except Exception as e:
+                error[0] = str(e)
+            done.set()
+
+        t = threading.Thread(target=run_estimate)
+        t.daemon = True
+        t.start()
+
+        while not done.is_set():
+            while gtk.events_pending():
+                gtk.main_iteration_do(False)
+            if done.wait(0.1):
+                break
+
+        dialog.hide()
+        dialog.destroy()
+
+        if error[0] is not None:
+            dialog = gtk.MessageDialog(
+                parent=self.main_window,
+                flags=gtk.DialogFlags.MODAL,
+                type=gtk.MessageType.ERROR,
+                buttons=gtk.ButtonsType.OK,
+                message_format="Estimation failed: " + error[0]
+            )
+            dialog.run()
+            dialog.destroy()
+            return
+
+        r = result[0]
+        total = r["total_time"]
+        exp_time = r["experiment_time"]
+        sleep_t = r["sleep_time"]
+        jobs = r["job_count"]
+
+        # format duration as HH:MM:SS
+        def fmt(seconds):
+            h = int(seconds) // 3600
+            m = (int(seconds) % 3600) // 60
+            s = int(seconds) % 60
+            return "%02d:%02d:%02d" % (h, m, s)
+
+        now = datetime.now()
+        end = now + timedelta(seconds=total)
+        end_str = end.strftime("%H:%M:%S")
+
+        text = (
+            "Jobs:            %d\n"
+            "Pulse program:   %s (%.2f s)\n"
+            "Sleeps:          %s (%.2f s)\n"
+            "---------------------------\n"
+            "Total:           %s\n\n"
+            "Start now:\n"
+            "Estimated end:   %s"
+        ) % (jobs, fmt(exp_time), exp_time, fmt(sleep_t), sleep_t, fmt(total), end_str)
+
+        dialog = gtk.MessageDialog(
+            parent=self.main_window,
+            flags=gtk.DialogFlags.MODAL,
+            type=gtk.MessageType.INFO,
+            buttons=gtk.ButtonsType.OK,
+            message_format=text
+        )
+        dialog.run()
+        dialog.destroy()
+
     def start_experiment( self, widget, data=None ):
 
         # something running?
diff --git a/src/damaris/gui/damaris3.glade b/src/damaris/gui/damaris3.glade
index a91e401..4483d3e 100644
--- a/src/damaris/gui/damaris3.glade
+++ b/src/damaris/gui/damaris3.glade
@@ -641,6 +641,21 @@ Public License instead of this License.
                 <property name="homogeneous">True</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkToolButton" id="toolbar_estimate_button">
+                <property name="visible">True</property>
+                <property name="can-focus">False</property>
+                <property name="tooltip-text" translatable="yes">Estimate experiment duration</property>
+                <property name="label">Estimate</property>
+                <property name="use-underline">True</property>
+                <property name="icon-name">dialog-information</property>
+                <signal name="clicked" handler="on_toolbar_estimate_button_clicked" swapped="no"/>
+              </object>
+              <packing>
+                <property name="expand">False</property>
+                <property name="homogeneous">True</property>
+              </packing>
+            </child>
             <child>
               <object class="GtkToolItem" id="toolitem4">
                 <property name="visible">True</property>