diff --git a/plot_stacked_bandwidth.py b/plot_stacked_bandwidth.py
index 16040eb..35d16cb 100755
--- a/plot_stacked_bandwidth.py
+++ b/plot_stacked_bandwidth.py
@@ -56,6 +56,6 @@ if __name__ == "__main__":
     L.get_texts()[5].set_text("4G SCC 4")
 
     if args.save:
-        plt.savefig("{}-used_bandwidth".format(args.save))
+        plt.savefig("{}-used_bandwidth.pdf".format(args.save))
     else:
         plt.show()