diff --git a/quiche/quic/core/quic_connection_test.cc b/quiche/quic/core/quic_connection_test.cc
index bcb09f9..2152a6f 100644
--- a/quiche/quic/core/quic_connection_test.cc
+++ b/quiche/quic/core/quic_connection_test.cc
@@ -8474,7 +8474,7 @@
   // that the encryption overhead is constant across versions.
   connection_.SetEncrypter(ENCRYPTION_INITIAL,
                            std::make_unique<TaggingEncrypter>(0x00));
-  QuicPacketLength expected_largest_payload = 1219;
+  QuicPacketLength expected_largest_payload = 1215;
   if (connection_.version().SendsVariableLengthPacketNumberInLongHeader()) {
     expected_largest_payload += 3;
   }
@@ -8509,7 +8509,7 @@
   // that the encryption overhead is constant across versions.
   connection_.SetEncrypter(ENCRYPTION_INITIAL,
                            std::make_unique<TaggingEncrypter>(0x00));
-  QuicPacketLength expected_largest_payload = 1219;
+  QuicPacketLength expected_largest_payload = 1215;
   if (connection_.version().HasLongHeaderLengths()) {
     expected_largest_payload -= 2;
   }
diff --git a/quiche/quic/test_tools/quic_test_utils.h b/quiche/quic/test_tools/quic_test_utils.h
index 0c0ab24..4c8c9b0 100644
--- a/quiche/quic/test_tools/quic_test_utils.h
+++ b/quiche/quic/test_tools/quic_test_utils.h
@@ -1721,7 +1721,7 @@
 
  private:
   enum {
-    kTagSize = 12,
+    kTagSize = 16,
   };
 
   const uint8_t tag_;
@@ -1784,7 +1784,7 @@
 
  private:
   enum {
-    kTagSize = 12,
+    kTagSize = 16,
   };
 
   bool CheckTag(absl::string_view ciphertext, uint8_t tag);