diff --git a/src/event/quic/ngx_event_quic_output.c b/src/event/quic/ngx_event_quic_output.c
index f98c834a1..c1d07650f 100644
--- a/src/event/quic/ngx_event_quic_output.c
+++ b/src/event/quic/ngx_event_quic_output.c
@@ -310,6 +310,10 @@ ngx_quic_allow_segmentation(ngx_connection_t *c)
     bytes = 0;
     len = ngx_min(qc->path->mtu, NGX_QUIC_MAX_UDP_SEGMENT_BUF);
 
+    if (qc->congestion.in_flight + len * 3 >= qc->congestion.window) {
+        return 0;
+    }
+
     for (q = ngx_queue_head(&ctx->frames);
          q != ngx_queue_sentinel(&ctx->frames);
          q = ngx_queue_next(q))
@@ -318,10 +322,6 @@ ngx_quic_allow_segmentation(ngx_connection_t *c)
 
         bytes += f->len;
 
-        if (qc->congestion.in_flight + bytes >= qc->congestion.window) {
-            return 0;
-        }
-
         if (bytes > len * 3) {
             /* require at least ~3 full packets to batch */
             return 1;