diff --git a/src/calibre/gui2/convert/regex_builder.ui b/src/calibre/gui2/convert/regex_builder.ui
index 63aaa89f36..e7b08928c1 100644
--- a/src/calibre/gui2/convert/regex_builder.ui
+++ b/src/calibre/gui2/convert/regex_builder.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>580</width>
-    <height>503</height>
+    <width>882</width>
+    <height>605</height>
    </rect>
   </property>
   <property name="windowTitle">