Time Value of Money (TVM)
Payment Mode Factor: S = 0 for End mode; 1 for Begin mode.
Amortization
ΣINT = accumulated interest
ΣPRN = accumulated principal
i = periodic interest rate
BAL is initially PV rounded to the current display setting.
PMT is initially PMT rounded to the current display setting.
For each payment amortized:
INT'
BAL × i (INT' is rounded to the current display setting;
=
INT' = 0 for period 0 in Begin mode.)
INT = INT' (with sign of PMT)
PRN = PMT + INT'
BAL
= BAL
new
old
ΣINT
= ΣINT
new
ΣPRN
= ΣPRN
new
Interest Rate Conversions
II
Appendix B: More About Calculations
⎛
i%
1
=
+
+
0
PV
---------------
⎝
100
+
+ PRN
+ INT
old
+ PRN
old
⎛
⎛
EFF%
=
1
⎝
⎝
I/YR
i%
------------ -
=
P/YR
⎛
i%
⎛
1
1
+
--------
–
⎝
⎜
100
×
⎞
S
×
×
⎜
------------------------------------- -
PMT
⎠
i%
⎜
------- -
⎝
100
–
⎛
i%
⎞
N
×
FV
1
+
------- -
⎝
⎠
100
⁄
I YR
i
=
-----------------------------
⁄
×
P YR
100
⁄
P YR
NOM%
⎞
⎞
×
1
+
–
-----------------------------
⎠
⎠
×
⁄
100
P YR
⎞
–
N
⎞
⎠
⎟
⎟
⎟
⎠
100