diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
index 7a91fcb63f..9b12b91ead 100644
--- a/app/test-pmd/csumonly.c
+++ b/app/test-pmd/csumonly.c
@@ -246,7 +246,7 @@ parse_gtp(struct rte_udp_hdr *udp_hdr,
 		info->l4_proto = 0;
 	}
 
-	info->l2_len += RTE_ETHER_GTP_HLEN;
+	info->l2_len += gtp_len + sizeof(udp_hdr);
 }
 
 /* Parse a vxlan header */