diff --git a/kitty/fonts/render.py b/kitty/fonts/render.py
index 2f1b0b04f..71e8e89f2 100644
--- a/kitty/fonts/render.py
+++ b/kitty/fonts/render.py
@@ -314,8 +314,7 @@ def render_special(
     dpi_x: float = 96.,
     dpi_y: float = 96.,
 ) -> CBufType:
-    udelta, uextra = divmod(underline_thickness, 2)
-    underline_position = min(underline_position, cell_height - udelta - uextra)
+    underline_position = min(underline_position, cell_height - sum(divmod(underline_thickness, 2)))
     CharTexture = ctypes.c_ubyte * (cell_width * cell_height)
 
     if missing: