I may have confused myself. I am trying to create a spreadsheet to figure out the different payments for different loan terms and payment methods (biweekly and monthly) since the calculators I see on the web require me to reenter information for each possible change in interest, down payment, loan term, amortization etc.
I started out with this formula:
P = L[c(1 + c)n]/[(1 + c)n - 1]
from the mortage professor
For the biweekly-payments, I made n = 26 * 30 = 780
vs n = 260
and made c = APR/26
vs APR/12
for monthly.
This is the math itself. However, after reading
With this payment method [biweekly], you pay $382 (half your monthly payment) every two weeks.
and
The only difference [with monthly payments] is that you structure your payments so that, instead of making one payment at the beginning of each month, you make half of one payment every two weeks.
and
The accepted answer (Noah's) here
I am not so sure if the method of paying every 2 weeks with n = 780
exists and would like to confirm so that I remove columns that pertain to this theoretical method.
I was also surprised when a mortgage broker in the US told me that he hasn't seen biweekly payments anywhere.