The calendar functions provided by the HP 12c, DATE and DELTA DYS, can handle dates from October 15, 1582 through November 25, 4046. The day of the week indicated by the DATE function may differ from that recorded in history for dates when the Julian calendar was in use. The Julian calendar was standard in England and its colonies until September 14,1752, when they switched to the Gregorian calendar. Other countries adopted the Gregorian calendar at various times.
For each of the calendar functions and for bond calculations (PRICE and YTM) the calculator uses one of the two date formats. The date format interprets dates when they are keyed into the calculator, and displays dates.
To set the date format to month-date-year, press g, then M.DY. Use the following instructions to key in a date with this format:
- Key in the one or two digits for the month.
- Press the decimal point key ( .).
- Key in the two digits of the day.
- Key in the four digits of the year.
- Dates are displayed in the same format. For example, to key in June 7, 2001:
To set the date format to day-month-year, press g, then D.MY. Use the following instructions to key in a date with this format:
- Key in the one or two digits of the day
- Press the decimal point key ( .)
- Key in the two digits for the month
- Key in the four digits for the year
- Dates are displayed in the same format. For example, to key in 7 June 2001:
When the date format is set to day-month-year, the D.MY status indicator in the display is lit. If D.MY is not lit, the date format is set to month-day-year. The date format remains set to that last specified until it is changed. It is not reset each time the calculator is turned on. However, if Continuous Memory is reset, the format is set to month-day-year.