diff --git a/src/twc.h b/src/twc.h
index ab4a1cd..8cd2275 100644
--- a/src/twc.h
+++ b/src/twc.h
@@ -33,7 +33,7 @@ enum t_twc_rc
 };
 
 #define TWC_MAX_FRIEND_MESSAGE_LENGTH (TOX_MAX_MESSAGE_LENGTH-1)
-#define TWC_MAX_GROUP_MESSAGE_LENGTH  (TOX_MAX_MESSAGE_LENGTH-9)
+#define TWC_MAX_GROUP_MESSAGE_LENGTH  (TOX_MAX_MESSAGE_LENGTH-16)
 
 #endif // TOX_WEECHAT_H