diff --git a/resources/default_tweaks.py b/resources/default_tweaks.py
index 644eb3042d..b035e31336 100644
--- a/resources/default_tweaks.py
+++ b/resources/default_tweaks.py
@@ -404,6 +404,13 @@ metadata_single_use_2_cols_for_custom_fields = True
 # metadata_edit_custom_column_order = ['#genre', '#mytags', '#etc']
 metadata_edit_custom_column_order = []
 
+#: Edit metadata custom column label width
+# Set the width of custom column labels shown in the edit metadata dialogs.
+# Labels longer than this length will be elided. The width is computed by
+# multiplying the average width of characters in the font by the number provided.
+metadata_edit_bulk_cc_label_width = 25
+metadata_edit_single_cc_label_width = 12
+
 #: The number of seconds to wait before sending emails
 # The number of seconds to wait before sending emails when using a
 # public email server like GMX/Hotmail/Gmail. Default is: 5 minutes
@@ -543,9 +550,3 @@ exclude_fields_on_paste = []
 # Useful if for some reason your operating systems network checking
 # facilities are not reliable (for example NetworkManager on Linux).
 skip_network_check = False
-
-#: Edit metadata custom column label width
-# Set the width of custom column labels shown in the edit metadata dialogs.
-# Labels longer than this length will be elided. The length is in 'n'self
-metadata_edit_bulk_cc_label_length = 25
-metadata_edit_single_cc_label_length = 10
diff --git a/src/calibre/gui2/custom_column_widgets.py b/src/calibre/gui2/custom_column_widgets.py
index a1c93229ff..8348476e7a 100644
--- a/src/calibre/gui2/custom_column_widgets.py
+++ b/src/calibre/gui2/custom_column_widgets.py
@@ -788,11 +788,11 @@ def populate_metadata_page(layout, db, book_id, bulk=False, two_column=False, pa
                 if label_width == 0:
                     font_metrics = wij.fontMetrics()
                     if bulk:
-                        label_width = font_metrics.width('n' *
-                                     tweaks['metadata_edit_bulk_cc_label_length'])
+                        label_width = (font_metrics.averageCharWidth() *
+                                       tweaks['metadata_edit_bulk_cc_label_length'])
                     else:
-                        label_width = font_metrics.width('n' *
-                                     tweaks['metadata_edit_single_cc_label_length'])
+                        label_width = (font_metrics.averageCharWidth() *
+                                       tweaks['metadata_edit_single_cc_label_length'])
                 wij.setMaximumWidth(label_width)
                 if c == 0:
                     wij.setSizePolicy(QSizePolicy.Maximum, QSizePolicy.Preferred)