diff --git a/iris/gui/widgets.py b/iris/gui/widgets.py
index c2a04028..a661d5c4 100644
--- a/iris/gui/widgets.py
+++ b/iris/gui/widgets.py
@@ -604,9 +604,6 @@ def update(self, *args):
             f = fluence(float(self.incident_laser_power_edit.text()),
                         int(self.laser_rep_rate_cb.currentText()),
                         FWHM = [int(self.beam_size_x_edit.text()), int(self.beam_size_y_edit.text())])
-            self.fluence.setText('{:2f}'.format(str(f)) + ' mJ / cm^2')
-        except ValueError:  # Could not parse 
-            self.fluence.setText('-----')
-
-
-        
\ No newline at end of file
+            self.fluence.setText('{:.2f}'.format(f) + ' mJ / cm^2')
+        except:  # Could not parse 
+            self.fluence.setText('-----')
\ No newline at end of file