diff --git a/src/util/src/ttime.c b/src/util/src/ttime.c
index 96e0eaa214fcb78269c26945ef04171c21aa66f7..7fb9738ec75ba722bc4d69ae872d5b4a0994e6ff 100644
--- a/src/util/src/ttime.c
+++ b/src/util/src/ttime.c
@@ -60,7 +60,7 @@ int64_t user_mktime64(const unsigned int year0, const unsigned int mon0,
   //               year*365 - 719499)*24 + hour)*60 + min)*60 + sec);
   int64_t res;
   res  = 367*((int64_t)mon)/12;
-  res += year/4 - year/100 + year/400 + day + year*365 - 719499;
+  res += year/4 - year/100 + year/400 + day + ((int64_t)year)*365 - 719499;
   res  = res*24;
   res  = ((res + hour) * 60 + min) * 60 + sec;