diff --git a/net/icmpv6/icmpv6_reply.c b/net/icmpv6/icmpv6_reply.c
index c309a8100a..3bd4192d52 100644
--- a/net/icmpv6/icmpv6_reply.c
+++ b/net/icmpv6/icmpv6_reply.c
@@ -139,7 +139,7 @@ void icmpv6_reply(FAR struct net_driver_s *dev, int type, int code, int data)
   /* Calculate the ICMPv6 checksum over the ICMPv6 header and payload. */
 
   icmpv6->chksum = 0;
-  icmpv6->chksum = ~icmpv6_chksum(dev, datalen + sizeof(*icmpv6));
+  icmpv6->chksum = ~icmpv6_chksum(dev, IPv6_HDRLEN);
   if (icmpv6->chksum == 0)
     {
       icmpv6->chksum = 0xffff;