diff --git a/wolfcrypt/src/kdf.c b/wolfcrypt/src/kdf.c
index 9fc56762b..30046f533 100644
--- a/wolfcrypt/src/kdf.c
+++ b/wolfcrypt/src/kdf.c
@@ -571,7 +571,7 @@ int wc_PRF_TLS(byte* digest, word32 digLen, const byte* secret, word32 secLen,
         (void)heap;
         /* okmLen (2) + protocol|label len (1) + info len(1) + protocollen +
          * labellen + infolen */
-        len = (size_t)4 + protocolLen + labelLen + infoLen;
+        len = 4U + protocolLen + labelLen + infoLen;
 
         data = (byte*)XMALLOC(len, heap, DYNAMIC_TYPE_TMP_BUFFER);
         if (data == NULL)