Rate
The interest rate per period.
Period
The period of the payment whose interest portion should be calculated, numbered from 1.
NumberOfPeriods
The total number of payment periods in the term.
PresentValue
The initial sum borrowed or invested.
FutureValue
The cash balance to be attained at the end of the term. (With a loan, this would normally be 0.) If omitted, it is assumed to be 0.
Type
0 If payments are made at the end of each period and 1 if payments are made at the start of each period (including a payment at the start of the term). If omitted, it is assumed to be 0.
Returns
The portion of the periodic payment which is interest.
Returns the interest portion of a specific periodic payment for a fixed-rate loan or annuity. Each payment consists of an interest portion and a principal portion. Use PPMT to obtain the principal portion.
Example
Returns roughly $-22.00. Consider a three-year loan of $8,000 at 6% annual interest with monthly end-of-month payments. In the 18th month, the interest portion of the monthly repayment is roughly $22.00. The result is negative because you pay this amount.