diff --git a/include/boost/date_time/gregorian_calendar.ipp b/include/boost/date_time/gregorian_calendar.ipp
index cb12640..c572a97 100644
--- a/include/boost/date_time/gregorian_calendar.ipp
+++ b/include/boost/date_time/gregorian_calendar.ipp
@@ -119,7 +119,7 @@ namespace date_time {
     date_int_type m = (5*e + 2)/153;
     unsigned short day = static_cast<unsigned short>(e - ((153*m + 2)/5) + 1);
     unsigned short month = static_cast<unsigned short>(m + 3 - 12 * (m/10));
-    date_int_type year = 100*b + d - 4800 + (m/10);
+    year_type year = static_cast<year_type>(100*b + d - 4800 + (m/10));
     //std::cout << year << "-" << month << "-" << day << "\n";
 
     return ymd_type(year,month,day);
@@ -139,7 +139,7 @@ namespace date_time {
     date_int_type m = (5*e + 2)/153;
     unsigned short day = e - ((153*m + 2)/5) + 1;
     unsigned short month = m + 3 - 12 * (m/10);
-    date_int_type year = 100*b + d - 4800 + (m/10);
+    year_type year = static_cast<year_type>(100*b + d - 4800 + (m/10));
     //std::cout << year << "-" << month << "-" << day << "\n";
     
     return ymd_type(year,month,day);