diff --git a/src/graph_tool/draw/cairo_draw.py b/src/graph_tool/draw/cairo_draw.py
index 7eadfc0d40dccfa1dc2509016f717effa81e1fab..8279b685a91c1cf86f5f98408a660b93277327e9 100644
--- a/src/graph_tool/draw/cairo_draw.py
+++ b/src/graph_tool/draw/cairo_draw.py
@@ -926,7 +926,7 @@ def get_bb(g, pos, size, pen_width, size_scale=1, text=None, font_family=None,
                 break
     sl = label_self_loops(g)
     slm = sl.a.max() * 0.75
-    delta = (size * size_scale * (slm + 1)) / 2 + pen_width
+    delta = (size * size_scale * (slm + 1)) / 2 + pen_width * 2
     x_range = [pos_x.fa.min(), pos_x.fa.max()]
     y_range = [pos_y.fa.min(), pos_y.fa.max()]
     x_delta = [x_range[0] - (pos_x.fa - delta).min(),