Language Guide

CHAPTER 6
Expressions
180 Operations
Date-Time Arithmetic 6
AppleScript supports these operations with the + and - operators on date and
time difference values:
date + timeDifference
--result: date
date - date
--result: timeDifference
date - timeDifference
--result: date
where date is a date value and timeDifference is an integer value specifying a
time difference in seconds.
To simplify the notation of time differences, you can also use one or more of
these constants:
Here’s an example:
date "Apr 15, 1992" + 4 * days + 3 * hours + 2 * minutes
It is often useful to be able to specify a time difference between two dates;
for example:
set timeInvestment to current date - "May 16, 1992"
After running this script, the value of the timeInvestment variable is an
integer that specifies the number of seconds between the two dates. If you then
add this time difference to the starting date (May 16, 1992), AppleScript returns
a date value equal to the current date when the timeInvestment variable
was set.
minutes 60
hours
60 * minutes
days
24 * hours
weeks
7 * days