diff --git a/include/polarssl/ssl.h b/include/polarssl/ssl.h
index 4b0c5f8..7e668f9 100644
--- a/include/polarssl/ssl.h
+++ b/include/polarssl/ssl.h
@@ -237,8 +237,8 @@
 #endif /* !POLARSSL_CONFIG_OPTIONS */
 
 /*
- * Allow an extra 512 bytes for the record header
- * and encryption overhead (counter + MAC + padding)
+ * Allow an extra 301 bytes for the record header
+ * and encryption overhead: counter (8) + header (5) + MAC (32) + padding (256)
  * and allow for a maximum of 1024 of compression expansion if
  * enabled.
  */
@@ -248,9 +248,9 @@
 #define SSL_COMPRESSION_ADD             0
 #endif
 
-#define SSL_BUFFER_LEN (SSL_MAX_CONTENT_LEN + SSL_COMPRESSION_ADD + 512)
+#define SSL_BUFFER_LEN (SSL_MAX_CONTENT_LEN + SSL_COMPRESSION_ADD + 301)
 
-#define SSL_EMPTY_RENEGOTIATION_INFO    0xFF   /**< renegotiation info ext */ 
+#define SSL_EMPTY_RENEGOTIATION_INFO    0xFF   /**< renegotiation info ext */
 
 /*
  * Supported Signature and Hash algorithms (For TLS 1.2)