diff --git a/easywsclient.cpp b/easywsclient.cpp
index f7068ac..bcc152d 100644
--- a/easywsclient.cpp
+++ b/easywsclient.cpp
@@ -252,7 +252,7 @@ class _RealWebSocket : public easywsclient::WebSocket
             ws.opcode = (wsheader_type::opcode_type) (data[0] & 0x0f);
             ws.mask = (data[1] & 0x80) == 0x80;
             ws.N0 = (data[1] & 0x7f);
-            ws.header_size = 2 + (ws.N0 == 126? 2 : 0) + (ws.N0 == 127? 6 : 0) + (ws.mask? 4 : 0);
+            ws.header_size = 2 + (ws.N0 == 126? 2 : 0) + (ws.N0 == 127? 8 : 0) + (ws.mask? 4 : 0);
             if (rxbuf.size() < ws.header_size) { return; /* Need: ws.header_size - rxbuf.size() */ }
             int i;
             if (ws.N0 < 126) {