diff --git a/nifty4/minimization/gradient_norm_controller.py b/nifty4/minimization/gradient_norm_controller.py
index 2c9c9a4f227b618161487b9e9f73b541332d6858..43f04709382dad42425eb21bf02a567ad9a583ad 100644
--- a/nifty4/minimization/gradient_norm_controller.py
+++ b/nifty4/minimization/gradient_norm_controller.py
@@ -61,8 +61,8 @@ class GradientNormController(IterationController):
             if self._name is not None:
                 msg += self._name+":"
             msg += " Iteration #" + str(self._itcount)
-            msg += " energy=" + str(energy.value)
-            msg += " gradnorm=" + str(energy.gradient_norm)
+            msg += " energy={:.2E}".format(energy.value)
+            msg += " gradnorm={:.2E}".format(energy.gradient_norm)
             msg += " clvl=" + str(self._ccount)
             dobj.mprint(msg)
             # self.logger.info(msg)