diff --git a/lib/idmapping.c b/lib/idmapping.c
index a4a4b681..da3ceefb 100644
--- a/lib/idmapping.c
+++ b/lib/idmapping.c
@@ -68,7 +68,10 @@ struct map_range *get_map_ranges(int ranges, int argc, char **argv)
 			free(mappings);
 			return NULL;
 		}
-		if (a2ul(&m->count, argv[argidx + 2], NULL, 0, 0, UINT_MAX) == -1) {
+		if (a2ul(&m->count, argv[argidx + 2], NULL, 0, 0,
+		         MIN(UINT_MAX - m->lower, UINT_MAX - m->upper))
+		    == -1)
+		{
 			if (errno == ERANGE) {
 				fprintf(log_get_logfd(), _( "%s: subuid overflow detected.\n"), log_get_progname());
 				exit(EXIT_FAILURE);
@@ -80,10 +83,6 @@ struct map_range *get_map_ranges(int ranges, int argc, char **argv)
 			fprintf(log_get_logfd(), _( "%s: subuid overflow detected.\n"), log_get_progname());
 			exit(EXIT_FAILURE);
 		}
-		if (m->lower + m->count > UINT_MAX || m->upper + m->count > UINT_MAX) {
-			fprintf(log_get_logfd(), _( "%s: subuid overflow detected.\n"), log_get_progname());
-			exit(EXIT_FAILURE);
-		}
 		if (m->lower + m->count < m->lower || m->upper + m->count < m->upper) {
 			/* this one really shouldn't be possible given previous checks */
 			fprintf(log_get_logfd(), _( "%s: subuid overflow detected.\n"), log_get_progname());