E-59
A
Calculation Formulas
a
: Interest portion of payment PM1 (INT)
INT
PM1
=
I
BAL
PM1–1
×
i
I
×
(
PMT
sign
)
b
: Principal portion of payment PM1 (PRN)
PRN
PM1
=
PMT
+
BAL
PM1–1
×
i
c
: Principal balance upon completion of payment PM2
(BAL)
BAL
PM2
=
BAL
PM2–1
+
PRN
PM2
d
: Total principal paid from payment PM1 to payment PM2
(
Σ
PRN)
Σ
PRN
=
PRN
PM1
+
PRN
PM1+1
+ … +
PRN
PM2
PM2
PM1
e
: Total interest paid from payment PM1 to payment PM2
(
Σ
INT)
•
a
+
b
= one repayment (PMT)
Σ
INT
=
INT
PM1
+
INT
PM1+1
+ … +
INT
PM2
PM2
PM1
BAL
0
= PV
....................... Payment: End
(Setup Screen)
INT
1
= 0
,
PRN
1
= PMT
... Payment: Begin
(Setup Screen)
Converting between the Nominal Interest Rate and
Effective Interest Rate
The nominal interest rate (
I
% value input by user) is
converted to an effective interest rate (
I
%´) for installment
loans where the number of annual payments is different
from the number of annual compoundings calculation
periods.
The following calculation is performed after conversion from
the nominal interest rate to the effective interest rate, and
the result is used for all subsequent calculations.
k
Conversion Mode
• The Conversion (CNVR) Mode lets you convert between
the nominal interest rate (APR) and effective interest rate
(EFF).
I%' =
I%
(1 +
)
–1
[
C
/
Y
]
[
P
/
Y
]
100
× [
C
/
Y
]
{
}
×
100
i = I%'
÷
100