256 Appendix E: Formulas Used
Compound Interest
Without an odd period:
0
PV
1 (
iS
)
=
+
+
With simple interest used for an odd period:
0
PV
1 [
i
FRAC(
=
+
INTG
−
FV
1 (
i
)
+
With compound interest used for an odd period:
FRAC(
0
PV
1 (
i
)
=
+
INTG
−
FV
1 (
i
)
+
Amortization
n
= number of payment periods to be amortized.
INT
= amount of PMT applied to interest in period j.
j
PRN
= amount of PMT applied to principal in period j.
j
PV
= present value (balance) of loan after payment in period j.
j
j
= period number.
INT
= {0 if n = 0 and payment mode is set to Begin.
1
|PV
0
PRN
= PMT – INT
1
PV
= PV
1
0
INT
= |PV
j
PRN
= PMT – INT
j
PV
= PV
j
j –1
n
∑
INT
∑
INT
=
j
j
1
=
n
∑
∑
PRN
=
PRN
j
1
=
∑
PV
PV
PRN
=
+
n
0
⎡
−
n
1
−
1 (
+
i
)
PMT
⋅
⋅
⎢
i
⎢
⎣
⎡
1
n
] )
1 (
iS
)
PMT
+
+
⎢
⎢
⎣
(
n
)
⎡
1
−
n
)
1 (
iS
)
PMT
+
+
⎢
⎢
⎣
(
n
)
× i|
(sign of PMT)
RND
1
+ PRN
1
× i|
× (sign of PMT) for j > 1.
j –1
RND
j
+ PRN
j
INT
INT
...
=
+
+
1
2
=
PRN
+
PRN
+
j
1
2
⎤
n
−
FV
1 (
i
)
+
+
⎥
⎥
⎦
INTG(
n
)
−
⎤
1 (
i
)
−
+
+
⎥
i
⎥
⎦
INTG(
n
)
−
⎤
1 (
i
)
+
+
⎥
i
⎥
⎦
INT
+
n
...
+
PRN
n