diff --git a/len.go b/runelength.go
similarity index 55%
rename from len.go
rename to runelength.go
index fed97be..df45ea6 100644
--- a/len.go
+++ b/runelength.go
@@ -1,31 +1,31 @@
 package utf8
 
-// Len returns the number of bytes in a UTF-8 encoding of this Unicode code point.
+// RuneLength returns the number of bytes in a UTF-8 encoding of this Unicode code point.
 //
 // Example
 //
-//	length := utf8.Len('A')
+//	length := utf8.RuneLength('A')
 //
 //	// length == 1
 //
 // Example
 //
-//	length := utf8.Len('r')
+//	length := utf8.RuneLength('r')
 //
 //	// length == 1
 //
 // Example
 //
-//	length := utf8.Len('¡')
+//	length := utf8.RuneLength('¡')
 //
 //	// length == 2
 //
 // Example
 //
-//	length := utf8.Len('۵')
+//	length := utf8.RuneLength('۵')
 //
 //	// length == 2
-func Len(r rune) int {
+func RuneLength(r rune) int {
 
 	switch {
 	case 127 >= r: