VMS Help FORTRAN, Intrinsic Procedures, SECNDS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  SECNDS (real-number)

  A subroutine that returns the number of seconds since midnight
  minus the value of the argument.  The argument must be a REAL*4
  data type.  The return value is a REAL*4 data type.  The time
  returned is accurate to .01 seconds.