diff --git a/libudev/libudev-util-private.c b/libudev/libudev-util-private.c
index fb64c13229c..e0670dbae5d 100644
--- a/libudev/libudev-util-private.c
+++ b/libudev/libudev-util-private.c
@@ -251,7 +251,7 @@ int util_run_program(struct udev *udev, const char *command, char **envp,
 	pid_t pid;
 	char arg[UTIL_PATH_SIZE];
 	char program[UTIL_PATH_SIZE];
-	char *argv[(sizeof(arg) / 2) + 1];
+	char *argv[((sizeof(arg) + 1) / 2) + 1];
 	int devnull;
 	int i;
 	int err = 0;