In order to create calc for a second date 10 days earlier than a entered date in "date1", 9/20/2006, for example:

"date2" = ( DayOfYear ( date1 ) -10 )

as a "number" yields the value "253"

In a new calc "date3", the value "253" returned as a date yields 9/10/0001.

I see that the day and month are correct but the year is off.

What am I missing?

FileMaker stores dates as numbers starting with 1/1/0001, so a answer of 253 is equal to the 253rd day of year 1

All you need to do is to subtract 10 for your date (or add 10) and you will get the result.

c_date2 (calculation, date result) =

date1 -10

a date result will equal 9/10/2006 if the field contents of date1 is 9/20/2006

HTH

Lee

Perfect -- that was so easy -- thank you:)