diff --git a/kitty/core_text.m b/kitty/core_text.m
index 8fda412a5..9736b5379 100644
--- a/kitty/core_text.m
+++ b/kitty/core_text.m
@@ -244,8 +244,9 @@ cell_metrics(PyObject *s, unsigned int* cell_width, unsigned int* cell_height, u
             if (w > width) width = w; 
         }
     }
-    *cell_width = width; 
-    *cell_height = (unsigned int)floor(self->ascent + self->descent + MAX(0, self->leading) + 0.5);  
+    *cell_width = MAX(1, width); 
+    float line_height = MAX(1, floor(self->ascent + self->descent + MAX(0, self->leading) + 0.5));
+    *cell_height = (unsigned int)line_height;  
     *underline_position = (unsigned int)self->underline_position;
     *underline_thickness = (unsigned int)self->underline_thickness;
     *baseline = (unsigned int)self->ascent;