| Syntax: | IPMT(R, P, NP, PV[, FV[, T]]) |
| XLIPMT(R, P, NP, PV, FV[, T]]) |
R = Interest rate per period
P = The period for which the interest will be calculated (an integer)
NP = The total number of payment periods
PV = The present value of the investment
FV = The future value or a cash balance you would like to
attain at the end of the last period
T = (Optional) timing of the payment:
| 0 | payment is made at the end of the period |
| 1 | payment is made at the beginning of the period |
IPMT returns the interest payment for a specified period for an loan or investment based on periodic, constant payments and a constant interest rate.
Make sure that the units used for R and P are consistent.
For example, for a 5-year loan with 12% annual interest,
if you make payments monthly, use 12%/12 for (monthly) R
and 
for NP.
If FV is omitted, it is assumed to be zero. Similarly, if T is omitted, it is assumed to be zero.
XLIPMT returns a negative value for consistency with Excel's IPMT. Otherwise, the two functions are identical.
Example:
IPMT(10%/12, 1, 24, 2000, 0, 0) = 16.6667
XLIPMT(10%/12, 1, 24, 2000, 0, 0) = -16.6667
IPMT(10%/12, 1, 24, 2000, 0, 0) = -16.6667 (in Excel compatibility mode)
Excel function: XLIPMT is compatible with Excel's IPMT (In Excel compatibility mode, the ``XL'' prefix is not used.)