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numpy.pv

# numpy.fv

`numpy.``fv`(rate, nper, pmt, pv, when='end')

  Compute the future value.

  Given:
    - a present value, `pv`
    - an interest `rate` compounded once per period, of which there are
    - `nper` total
    - a (fixed) payment, `pmt`, paid either
    - at the beginning (when = {‘begin’, 1}) or the end (when = {‘end’, 0}) of each period
  Return:
    the value at the end of the `nper` periods

  Parameters: | rate : scalar or array_like of shape(M, ) Rate of interest as decimal (not per cent) per period nper : scalar or array_like of shape(M, ) Number of compounding periods pmt : scalar or array_like of shape(M, ) Payment pv : scalar or array_like of shape(M, ) Present value when : {{‘begin’, 1}, {‘end’, 0}}, {string, int}, optional When payments are due (‘begin’ (1) or ‘end’ (0)). Defaults to {‘end’, 0}.
  Returns: | out : ndarray Future values. If all input is scalar, returns a scalar float. If any input is array_like, returns future values for each input element. If multiple inputs are array_like, they all must have the same shape.

  Notes

  The future value is computed by solving the equation:

      fv +
      pv*(1+rate)**nper +
      pmt*(1 + rate*when)/rate*((1 + rate)**nper - 1) == 0

  or, when `rate == 0`:

      fv + pv + pmt * nper == 0

  References

  [WRW] | Wheeler, D. A., E. Rathke, and R. Weir (Eds.) (2009, May). Open Document Format for Office Applications (OpenDocument)v1.2, Part 2: Recalculated Formula (OpenFormula) Format - Annotated Version, Pre-Draft 12. Organization for the Advancement of Structured Information Standards (OASIS). Billerica, MA, USA. [ODT Document]. Available: http://www.oasis-open.org/committees/documents.php?wg_abbrev=office-formula OpenDocument-formula-20090508.odt

  Examples

  What is the future value after 10 years of saving $100 now, with an additional monthly savings of $100. Assume the interest rate is 5% (annually) compounded monthly?

      >>> np.fv(0.05/12, 10*12, -100, -100)
      15692.928894335748

  By convention, the negative sign represents cash flow out (i.e. money not available today). Thus, saving $100 a month at 5% annual interest leads to $15,692.93 available to spend in 10 years.

  If any input is array_like, returns an array of equal shape. Let’s compare different interest rates from the example above.

      >>> a = np.array((0.05, 0.06, 0.07))/12
      >>> np.fv(a, 10*12, -100, -100)
      array([ 15692.92889434,  16569.87435405,  17509.44688102])