diff --git a/src/cli/cli.cpp b/src/cli/cli.cpp
index 7e4d1f69f..99b13b03c 100644
--- a/src/cli/cli.cpp
+++ b/src/cli/cli.cpp
@@ -2994,8 +2994,8 @@ void Interpreter::HandleSntpResponse(uint64_t aTime, otError aResult)
     {
         // Some Embedded C libraries do not support printing of 64-bit unsigned integers.
         // To simplify, unix epoch time and era number are printed separately.
-        mServer->OutputFormat("SNTP response - Unix time: %ld (era: %ld)\r\n",
-                              static_cast<uint32_t>(aTime & UINT32_MAX), static_cast<uint32_t>(aTime >> 32));
+        mServer->OutputFormat("SNTP response - Unix time: %ld (era: %ld)\r\n", static_cast<uint32_t>(aTime),
+                              static_cast<uint32_t>(aTime >> 32));
     }
     else
     {
diff --git a/src/core/net/sntp_client.cpp b/src/core/net/sntp_client.cpp
index ac5da715f..fd9c051cf 100644
--- a/src/core/net/sntp_client.cpp
+++ b/src/core/net/sntp_client.cpp
@@ -374,7 +374,7 @@ void Client::HandleUdpReceive(Message &aMessage, const Ip6::MessageInfo &aMessag
     // Due to NTP protocol limitation, this module stops working correctly after around year 2106, if
     // unix era is not updated. This seems to be a reasonable limitation for now. Era number cannot be
     // obtained using NTP protocol, and client of this module is responsible to set it properly.
-    unixTime = GetUnixEra() * (UINT32_MAX + 1ULL);
+    unixTime = GetUnixEra() * (1ULL << 32);
 
     if (responseHeader.GetTransmitTimestampSeconds() > kTimeAt1970)
     {
@@ -382,8 +382,7 @@ void Client::HandleUdpReceive(Message &aMessage, const Ip6::MessageInfo &aMessag
     }
     else
     {
-        unixTime +=
-            static_cast<uint64_t>(responseHeader.GetTransmitTimestampSeconds()) + (UINT32_MAX + 1ULL) - kTimeAt1970;
+        unixTime += static_cast<uint64_t>(responseHeader.GetTransmitTimestampSeconds()) + (1ULL << 32) - kTimeAt1970;
     }
 
     // Return the time since 1970.