Excel - Mortgage Principal Paid over a Period

Interested in determining how much principal is paid on a mortgage between two time periods?


CUMPRINC(Rate, nper, pv, start_period, end_period, type)

Example: How much principal will a borrower pay between their 10 and 15 payment on their mortgage?  Principal balance at the starting period is $51000 and interest rate in 9%.

Rate - it's the interest rate for the period, so for a mortgage with 9% you need to divide by 12 to get the monthly interest rate, .09/12

nper - total number of payments to be included, so the number of months between the start period and end period  (15-10), 5

pv - the principal at the starting period

Start_Period - Payment date doesn't work, you have to figure out the payment number, i.e. the 10th payment out of the term. 10

End_Period - Again, not a date, it has to be the number of the last payment, 15

Type - set it to 0 if the payment is made on the first of the month, 1 of the payment is on the end of the month

=CumPrinc( .09/12, 5, 51000, 10, 15)

Cumulative Principal Paid Between Periods