diff --git a/src/ISO8601.cpp b/src/ISO8601.cpp
index c8c1631cb..881ca3849 100644
--- a/src/ISO8601.cpp
+++ b/src/ISO8601.cpp
@@ -913,6 +913,12 @@ int ISO8601d::month () const
   return t->tm_mon + 1;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+int ISO8601d::week () const
+{
+  return ISO8601d::weekOfYear (ISO8601d::dayOfWeek (ISO8601d::weekstart));
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 void ISO8601p::clear ()
 {
diff --git a/src/ISO8601.h b/src/ISO8601.h
index 466e40d7e..9889da8fd 100644
--- a/src/ISO8601.h
+++ b/src/ISO8601.h
@@ -54,6 +54,7 @@ public:
   static int length (const std::string&);
 
   int month () const;
+  int week () const;
 
 private:
   void clear ();