cf

Format: cf( term, rate, pv, pmt, fv, begin, compound )

Arguments: (real) term Number of periods

(real) rate Periodic interest rate

(real) pv Present value

(real) pmt Periodic payment

(real) fv Future value

(bool) begin Optional flag indicating if payments are at the beginning or end of each period; default = false (end)

(bool) compound Optional flag indicating if compound or simple interest should be accrued in odd first periods; default = false (simple)

Returns: (real) The unknown quantity corresponding to the input argument that has a value of null

Description: Given four of the five terms defining a cash flow series (term, rate, pv, pmt, and fv) cf will solve for the fifth. You specify which term to solve for by entering the value null for the corresponding input argument.

The diagram below illustrates the series of cash flows that the values term, pv, pmt and fv represent.

All cash flows in this diagram are show as positive; but it is common that one or more of the cash flows will be negative. Be sure to use the proper sign when specifying cash flow values. By convention, cash coming in is positive and cash going out is negative.

In the diagram above, all periodic payments are assumed to be at the end of each period. This means that the first cash flow is pv and the last is fv + pmt. You can cause all payments to be at the end or beginning of each period using the begin argument. When begin is true, the first cash flow is pv + pmt and the last is fv.

begin = true:

begin = false:

If term contains a fractional component, the fractional component is assumed to represent an odd first period. For example, if term is 6.50, there are 6 periods and the first period is longer than the remaining 5.

In odd period calculations, interest for the odd period can be accrued using simple or compound interest. Compound interest is used if the compound argument is true, otherwise, simple interest is used

Examples: cf(5*12,7.5%/12,20000,null,0) = -400.76  (calculate monthly payments for a 5-year 7.5% loan of $20,000)

cf(null,7.5%/12,20000,-401,0) = 60  (calculate the number of periods required in the problem above)

See Also: npv, irr, pv, pmt, fv, rate, term