diff --git a/Lib/idlelib/configHandler.py b/Lib/idlelib/configHandler.py
index efd5f3ce4f..4c95a39239 100644
--- a/Lib/idlelib/configHandler.py
+++ b/Lib/idlelib/configHandler.py
@@ -721,7 +721,7 @@ class IdleConf:
                 actualFont = Font.actual(f)
                 family = actualFont['family']
                 size = actualFont['size']
-                if size < 0:
+                if size <= 0:
                     size = 10  # if font in pixels, ignore actual size
                 bold = actualFont['weight']=='bold'
         return (family, size, 'bold' if bold else 'normal')