diff --git a/src/calibre/gui2/dialogs/select_formats.py b/src/calibre/gui2/dialogs/select_formats.py
index baae2f50f4..d1de9b5202 100644
--- a/src/calibre/gui2/dialogs/select_formats.py
+++ b/src/calibre/gui2/dialogs/select_formats.py
@@ -35,9 +35,9 @@ class Formats(QAbstractListModel):
         if role == Qt.ToolTipRole:
             fmt = self.fmts[row]
             count = self.counts[fmt]
-            return (
-                _('There are %(count)d book(s) with the %(fmt)s format')%dict(
-                    count=count, fmt=fmt.upper()))
+            return ngettext('There is one book with the {fmt} format',
+                            'There are {count} books with the {fmt} format', count).format(
+                                count=count, fmt=fmt.upper())
         return None
 
     def flags(self, index):