diff --git a/Jupiter/Readable_String.h b/Jupiter/Readable_String.h
index ced8b70..f5db4eb 100644
--- a/Jupiter/Readable_String.h
+++ b/Jupiter/Readable_String.h
@@ -81,6 +81,15 @@ namespace Jupiter
 		size_t find(const T &value, size_t index = 0) const;
 		size_t find(const Readable_String<T> &in) const;
 
+		/**
+		* @brief Returns the number of elements of the string which match the input string.
+		*
+		* @param in Character set to match against.
+		* @return Number of elements at the start of the string that match the character set.
+		*/
+		size_t span(const Readable_String<T> &in) const;
+		size_t span(const T *str) const;
+
 		/**
 		* @brief Compares another string against the String.
 		*
diff --git a/Jupiter/Readable_String_Imp.h b/Jupiter/Readable_String_Imp.h
index 3dde809..1055b61 100644
--- a/Jupiter/Readable_String_Imp.h
+++ b/Jupiter/Readable_String_Imp.h
@@ -68,6 +68,22 @@ template<typename T> size_t Jupiter::Readable_String<T>::find(const Jupiter::Rea
 	return Jupiter::INVALID_INDEX;
 }
 
+// span()
+
+template<typename T> size_t Jupiter::Readable_String<T>::span(const Jupiter::Readable_String<T> &in) const
+{
+	size_t index = 0;
+	while (in.contains(this->get(index))) index++;
+	return index;
+}
+
+template<typename T> size_t Jupiter::Readable_String<T>::span(const T *in) const
+{
+	size_t index = 0;
+	while (containsSymbol(in, this->get(index))) index++;
+	return index;
+}
+
 // compare()
 
 template<typename T> int Jupiter::Readable_String<T>::compare(const Jupiter::Readable_String<T> &in) const