diff --git a/hardware/arduino/avr/cores/arduino/WString.cpp b/hardware/arduino/avr/cores/arduino/WString.cpp
index 998cf22d38f..f2572d60883 100644
--- a/hardware/arduino/avr/cores/arduino/WString.cpp
+++ b/hardware/arduino/avr/cores/arduino/WString.cpp
@@ -745,6 +745,6 @@ float String::toFloat(void) const
 
 double String::toDouble(void) const
 {
-    if (buffer) return atof(buffer);
-    return 0;
-}
\ No newline at end of file
+	if (buffer) return atof(buffer);
+	return 0;
+}
diff --git a/hardware/arduino/avr/cores/arduino/WString.h b/hardware/arduino/avr/cores/arduino/WString.h
index 08b8147bcfe..77709c3ba42 100644
--- a/hardware/arduino/avr/cores/arduino/WString.h
+++ b/hardware/arduino/avr/cores/arduino/WString.h
@@ -190,7 +190,7 @@ class String
 	// parsing/conversion
 	long toInt(void) const;
 	float toFloat(void) const;
-    double toDouble(void) const;
+	double toDouble(void) const;
 
 protected:
 	char *buffer;	        // the actual char array
diff --git a/hardware/arduino/sam/cores/arduino/WString.cpp b/hardware/arduino/sam/cores/arduino/WString.cpp
index e4efc7d4f55..71bbc07d13b 100644
--- a/hardware/arduino/sam/cores/arduino/WString.cpp
+++ b/hardware/arduino/sam/cores/arduino/WString.cpp
@@ -747,6 +747,6 @@ float String::toFloat(void) const
 
 double String::toDouble(void) const
 {
-    if (buffer) return atof(buffer);
-    return 0;
-}
\ No newline at end of file
+	if (buffer) return atof(buffer);
+	return 0;
+}
diff --git a/hardware/arduino/sam/cores/arduino/WString.h b/hardware/arduino/sam/cores/arduino/WString.h
index 08b8147bcfe..77709c3ba42 100644
--- a/hardware/arduino/sam/cores/arduino/WString.h
+++ b/hardware/arduino/sam/cores/arduino/WString.h
@@ -190,7 +190,7 @@ class String
 	// parsing/conversion
 	long toInt(void) const;
 	float toFloat(void) const;
-    double toDouble(void) const;
+	double toDouble(void) const;
 
 protected:
 	char *buffer;	        // the actual char array