Navigation: Templates > Guide to all Templates > Additional Libraries and Templates > Finance Library >====== PREPERS (periods of annuity with prepayment) ====== | |

**PREPERS**(*presentvalue,rate,payment,futurevalue*)

PREPERS | Computes the number of periods required to reach a targeted future value. |

presentvalue | A numeric constant or variable containing the present value of the investment. |

rate | A numeric constant or variable containing the periodic rate of return. |

payment | A numeric constant or variable containing the periodic payment. |

futurevalue | A numeric constant or variable containing the amount of the desired or targeted future value of the investment. |

**PREPERS **determines the number of periods required to reach a desired amount (*futurevalue*) based upon a starting amount (*presentvalue*), a periodic interest rate (*rate*), and a payment amount (*payment*). If payments occur at the end of each period, use the PERS function, which calculates interest accordingly.

Periodic rate may be calculated as follows:

PeriodicRate = AnnualInterestRate / (PeriodsPerYear * 100)

If the present value is less than the future value (annuities), payments are positive, and conversely, if the present value is greater than the future value (loans), payments are negative.

**Return Data Type:** DECIMAL

**Internal Formulas:**

The PREPERS function performs binary search iterations to home in on the periods value. If more than 50 such iterations are required, a value of zero is returned.

**Example:**

** PeriodicRate = AnnualRate / (PeriodsPerYear * 100)**

** IF TimeOfPayment = 'Beginning of Periods'**

** TotalPeriods = PREPERS(PresentValue,PeriodicRate,Payment,FutureValue)**

** ELSE**

** TotalPeriods = PERS(PresentValue,PeriodicRate,Payment,FutureValue)**

** END**