diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 34e0ee58f8..65219798e9 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -18929,7 +18929,7 @@ zonemgr_keymgmt_delete(dns_zonemgr_t *zmgr, dns_zone_t *zone) {
 		if (dns_name_equal(kfio->name, &zone->origin)) {
 			unsigned int count;
 
-			count = atomic_fetch_sub_relaxed(&kfio->count, 1);
+			count = atomic_fetch_sub_relaxed(&kfio->count, 1) - 1;
 			if (count > 0) {
 				/* Keep the entry. */
 				break;