diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index bdf282ec..a0dccd39 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -5853,7 +5853,8 @@ int nghttp2_session_recv(nghttp2_session *session) {
  * reserved state.
  */
 static size_t session_get_num_active_streams(nghttp2_session *session) {
-  return nghttp2_map_size(&session->streams) - session->num_closed_streams;
+  return nghttp2_map_size(&session->streams) - session->num_closed_streams -
+         session->num_idle_streams;
 }
 
 int nghttp2_session_want_read(nghttp2_session *session) {