diff --git a/artiq/frontend/artiq_master.py b/artiq/frontend/artiq_master.py
index a41091feb..8c82de7c7 100755
--- a/artiq/frontend/artiq_master.py
+++ b/artiq/frontend/artiq_master.py
@@ -22,10 +22,10 @@ def get_argparser():
         help="hostname or IP address to bind to")
     group.add_argument(
         "--port-notify", default=3250, type=int,
-        help="TCP port to listen to for notifications (default: 3250)")
+        help="TCP port to listen to for notifications (default: %(default)d)")
     group.add_argument(
         "--port-control", default=3251, type=int,
-        help="TCP port to listen to for control (default: 3251)")
+        help="TCP port to listen to for control (default: %(default)d)")
     verbosity_args(parser)
     return parser
 
diff --git a/artiq/tools.py b/artiq/tools.py
index 5455996e4..464c38c79 100644
--- a/artiq/tools.py
+++ b/artiq/tools.py
@@ -54,8 +54,7 @@ def simple_network_args(parser, default_port):
     group.add_argument("--bind", default="::1",
                        help="hostname or IP address to bind to")
     group.add_argument("-p", "--port", default=default_port, type=int,
-                       help="TCP port to listen to (default: {})"
-                       .format(default_port))
+                       help="TCP port to listen to (default: %(default)d)")
 
 
 def init_logger(args):