Texas Instruments BA II PLUS User Manual page 130

30/360 day-count method
(assumes 30 days per month and 360 days per year):
=
DBD ( Y
where:
Note: If DT1 is 31, change DT1 to 30. If DT2 is 31 and DT1 is 30 or 31,
change DT2 to 30; otherwise, leave it at 31.
Source for 30/360 day-count method formula: Lynch, John J.,
Jr., and Jan H. Mayle. Standard Securities Calculation
Methods. New York: Securities Industry Association, 1986.
124
− × +
2 Y 1 ) 360 ( M 2
M1 = month of first date
DT1 = day of first date
Y1 = year of first date
M2 = month of second date
DT2 = day of second date
Y2 = year of second date
− × + −
M 1 ) 30 ( DT 2
BA II PLUS™ Calculator
DT 1 )