Date and time values in Excel (and Access etc)

Date/time values are stored internally in Excel as a real number where the apparent integer part and the mantissa part are interpreted as simple counts or fractions respectively.

• The data component is represented internally in Excel as the 'number of days elapsed since 12/30/1899.
• The time component is represented internally in Excel as the fraction of 24 hours.

Consider the following example:
Create your own test by entering January 26, 2011 9:00 PM the date into an Excel cell, e.g.

26/01/2001 21:00

Excel's auto format will usually recognise it as a date and record it (internally) as a date time.
Now change the cell format to General. You should see the following displayed.

36917.875

Date component	separator	Time component
36917	.	875

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The mantissa part (the 'fraction part', everything after the decimal point or separator, also called a 'significand') is a decimal fraction of 24 hours.

The integer part is (the whole number in front of the decimal point or separator) is simply the number of whole days.

Question: does the actual internal representation in Excel map to a double precision floating point number or two integers?