I need help with an interest rate calculation.
Given:
P = Principal
i = APR
n = frequency of payments/compounding per year
Y = number of years to repay
B = Final Balloon Payment
how do I calculate the per period payment?
“Bill Caroselli (Q-TPS)” <QTPS@earthlink.net> wrote:
I need help with an interest rate calculation.
Given:
P = Principal
i = APR
n = frequency of payments/compounding per year
Y = number of years to repay
B = Final Balloon Paymenthow do I calculate the per period payment?
Here’s my list of handy formulas, not sure if the one you want is in there somewhere 
Financial mathematics:
Future worth of a present amount:
(F/P, i, N) = (1 + i) ^ n = e ^ (j * n)
Present worth of a future amount:
(P/F, i, N) = 1 / ((1 + i) ^ n) = e ^ (-j * n)
Future worth of an annuity:
(F/A, i, N) = ((1 + i) ^ n - 1) / i = (e ^ j * n - 1) / (e ^ j - 1)
Annuity for a future amount:
(A/F, i, N) = i / ((1 + i) ^ n - 1) = (e ^ j - 1) / (e ^ (j * n) - 1)
Present worth of an annuity:
(P/A, i, N) = ((1 + i) ^ n - 1) / (i * (1 + i) ^ n) = (e ^ (j * n) - 1) / ((e ^ j - 1) * e ^ (j * n))
Annuity from a present amount:
(A/P, i, N) = (i * (1 + i) ^ n) / ((1 + i) ^ n) - 1) = ((e ^ j - 1) * e ^ (j * n)) / (e ^ (j * n) - 1)
Future worth of a continuous annuity:
(F/A’, j, N) = ((1 + i) ^ n - 1) / j = (e ^ (j * n) - 1) / j
Present worth of a continuous annuity:
(P/A’, j, N) = ((1 + i) ^ n - 1) / (j * (1 + i) ^ n) = (e ^ (j * n) - 1) / (j * e ^ (j * n))
Continuous annuity from a present amount:
(A’/P, j, N) = (j * (1 + i) ^ n) / ((1 + i ^ n - 1) = (j * e ^ (j * n)) / (e ^ (j * n) - 1)
Continuous annuity for a future amount:
(A’/F, j, N) = j / ((1 + i) ^ n - 1) = j / (e ^ (j * n) - 1)
–
Robert Krten, PARSE Software Devices +1 613 599 8316.
Realtime Systems Architecture, Books, Video-based and Instructor-led
Training and Consulting at www.parse.com.
Email my initials at parse dot com.
Good! I hate talking about work at the cafe!
“Bill Caroselli (Q-TPS)” wrote:
I need help with an interest rate calculation.
Given:
P = Principal
i = APR
n = frequency of payments/compounding per year
Y = number of years to repay
B = Final Balloon Paymenthow do I calculate the per period payment?
Yawn. I call my accountant…
Seriously, it looks like an interesting question. I bet it isn’t in any
financial calculator, nor in Rob’s handy list, either. It’s that
arbitrary Final Balloon Payment; if it was zero one of the standard
formulas would handle it. Hmmm, time for more coffee…
Phil
“Phil Olynyk” <pholynyk@rogers.com> wrote in message
news:3CB2EA0E.10765F15@rogers.com…
Good! I hate talking about work at the cafe!
Seriously, it looks like an interesting question. I bet it isn’t in any
financial calculator, nor in Rob’s handy list, either. It’s that
arbitrary Final Balloon Payment; if it was zero one of the standard
formulas would handle it. Hmmm, time for more coffee…Phil
I mean I know how to do an amortization table. I can use trial and error
until I get to the correct cent. But I know that there is some crazy log
formula that will do it in one shot.
Bill Caroselli (Q-TPS) wrote:
“Phil Olynyk” <> pholynyk@rogers.com> > wrote in message
news:> 3CB2EA0E.10765F15@rogers.com> …Good! I hate talking about work at the cafe!
Seriously, it looks like an interesting question. I bet it isn’t in any
financial calculator, nor in Rob’s handy list, either. It’s that
arbitrary Final Balloon Payment; if it was zero one of the standard
formulas would handle it. Hmmm, time for more coffee…Phil
I mean I know how to do an amortization table. I can use trial and error
until I get to the correct cent. But I know that there is some crazy log
formula that will do it in one shot.How about a root solver? Netwon’s methos works fine on this equation.
“David Hawley” <david.l.hawley@computer.org> wrote in message
news:3CB50851.2000304@computer.org…
How about a root solver? Netwon’s methos works fine on this equation.
Newton? That guy got hit on the head by too many apples! (I think they
were the 2E’s)
For Sale:
Engineering Economy
William G. Sullivan
11th Edition
$99 new at Amazon, $45 new from me.
Has all the good formulas with their backgrounders.
I love Information Technology Science; you know: operating systems,
integrated circuit design, crypto, engineering economy…
Leon Woestenberg.
P.S. Just kidding guys - (but the book is for sale
“Bill Caroselli (Q-TPS)” <QTPS@EarthLink.net> wrote in message
news:a8srlj$6of$1@inn.qnx.com…
I need help with an interest rate calculation.
Given:
P = Principal
i = APR
n = frequency of payments/compounding per year
Y = number of years to repay
B = Final Balloon Paymenthow do I calculate the per period payment?