diff --git a/src/MFRC522v2-NDEF/record.cpp b/src/MFRC522v2-NDEF/record.cpp
index 691d9f5..4c33453 100644
--- a/src/MFRC522v2-NDEF/record.cpp
+++ b/src/MFRC522v2-NDEF/record.cpp
@@ -54,7 +54,7 @@ uint8_t *NdefRecord::encode() const
   return result;
 }
 
-uint32_t NdefRecord::get_encoded_size()
+uint32_t NdefRecord::get_encoded_size() const
 {
   return 2                                 // TNF + flags + type length
        + (_payload.length() > 255 ? 4 : 1) // payload length size
diff --git a/src/MFRC522v2-NDEF/record.hpp b/src/MFRC522v2-NDEF/record.hpp
index f49427d..0b6da28 100644
--- a/src/MFRC522v2-NDEF/record.hpp
+++ b/src/MFRC522v2-NDEF/record.hpp
@@ -92,7 +92,7 @@ class NdefRecord
      *
      * @return uint32_t Encoded size
      */
-    uint32_t get_encoded_size();
+    uint32_t get_encoded_size() const;
 
     /**
      * @brief Encode the NDEF record