diff --git a/kitty/config_data.py b/kitty/config_data.py
index 4f13ae6fe..34c225525 100644
--- a/kitty/config_data.py
+++ b/kitty/config_data.py
@@ -227,6 +227,7 @@ def adjust_line_height(x):
         if ans < 0:
             log_error('Percentage adjustments of cell sizes must be positive numbers')
             return 0
+        return ans
     return int(x)