diff --git a/src/ArduinoJson/Json/TextFormatter.hpp b/src/ArduinoJson/Json/TextFormatter.hpp
index 18694f14..7795671f 100644
--- a/src/ArduinoJson/Json/TextFormatter.hpp
+++ b/src/ArduinoJson/Json/TextFormatter.hpp
@@ -155,7 +155,6 @@ class TextFormatter {
 
  protected:
   CountingDecorator<TWriter> _writer;
-  size_t _length;
 
  private:
   TextFormatter &operator=(const TextFormatter &);  // cannot be assigned