Financial functions

Excel's financial functions work out loans, savings and investments.

• ACCRINT: accrued interest on a security.
• CUMIPMT: total interest paid between two periods.
• PV(rate, nper, pmt, fv, type): present value, for example how big a loan you can take.
• FV(rate, nper, pmt, pv, type): future value of regular payments.
• PMT(rate, nper, pv, [fv], [type]): the equal payment each period. ₹10,000 over four years at 12% a year comes to about ₹263.34 a month.

Three rules that catch students:

• Rate and nper must use the same period. Paid monthly, a 10% yearly rate becomes 10%/12, and a four-year loan has 48 periods.
• Type 0 means payments at the end of each period; type 1 at the beginning.
• Money paid out is negative, money received is positive.

Three more: RATE finds the interest rate by trying again and again (iteration), and gives #NUM! if it cannot settle on an answer. NPV(rate, value1, value2...) discounts unequal future cash flows, each at the end of its period. IRR is the rate at which NPV becomes zero.