diff --git a/src/calibre/gui2/convert/single.py b/src/calibre/gui2/convert/single.py
index 8aaa9de7cd..4f91d848d8 100644
--- a/src/calibre/gui2/convert/single.py
+++ b/src/calibre/gui2/convert/single.py
@@ -153,7 +153,7 @@ class Config(ResizableDialog, Ui_Dialog):
         except ImportError:
             pass
         input_widget = None
-        name = 'calibre.gui2.convert.%s' % self.plumber.input_plugin.name.lower().replace(' ', '_')
+        name = self.plumber.input_plugin.name.lower().replace(' ', '_')
         try:
             input_widget = __import__('calibre.gui2.convert.'+name,
                         fromlist=[1])