diff --git a/backend/wayland/output.c b/backend/wayland/output.c
index ba435c25..0f314031 100644
--- a/backend/wayland/output.c
+++ b/backend/wayland/output.c
@@ -290,8 +290,8 @@ struct wlr_output *wlr_wl_output_create(struct wlr_backend *wlr_backend) {
 	wlr_output_update_custom_mode(wlr_output, 1280, 720, 0);
 	strncpy(wlr_output->make, "wayland", sizeof(wlr_output->make));
 	strncpy(wlr_output->model, "wayland", sizeof(wlr_output->model));
-	snprintf(wlr_output->name, sizeof(wlr_output->name), "WL-%d",
-		wl_list_length(&backend->outputs) + 1);
+	snprintf(wlr_output->name, sizeof(wlr_output->name), "WL-%lu",
+		++backend->last_output_num);
 
 	output->backend = backend;
 
diff --git a/include/backend/wayland.h b/include/backend/wayland.h
index c41d560a..c0bb6e74 100644
--- a/include/backend/wayland.h
+++ b/include/backend/wayland.h
@@ -24,6 +24,7 @@ struct wlr_wl_backend {
 	struct wlr_egl egl;
 	struct wlr_renderer *renderer;
 	size_t requested_outputs;
+	size_t last_output_num;
 	struct wl_listener local_display_destroy;
 	/* remote state */
 	struct wl_display *remote_display;