diff --git a/fhem/FHEM/73_ElectricityCalculator.pm b/fhem/FHEM/73_ElectricityCalculator.pm
index d8cb27f44..664926111 100644
--- a/fhem/FHEM/73_ElectricityCalculator.pm
+++ b/fhem/FHEM/73_ElectricityCalculator.pm
@@ -9,7 +9,7 @@
 #
 #     Author                     : Matthias Deeke 
 #     e-mail                     : matthias.deeke(AT)deeke(PUNKT)eu
-#     Fhem Forum                 : Not yet implemented
+#     Fhem Forum                 : https://forum.fhem.de/index.php/topic,57106.msg485195.html
 #     Fhem Wiki                  : Not yet implemented
 #
 #     This file is part of fhem.