# numpy.rate¶

`numpy.``rate`(nper, pmt, pv, fv, when='end', guess=None, tol=None, maxiter=100)[source]

Compute the rate of interest per period.

Parameters: nper : array_like Number of compounding periods pmt : array_like Payment pv : array_like Present value fv : array_like Future value when : {{‘begin’, 1}, {‘end’, 0}}, {string, int}, optional When payments are due (‘begin’ (1) or ‘end’ (0)) guess : Number, optional Starting guess for solving the rate of interest, default 0.1 tol : Number, optional Required tolerance for the solution, default 1e-6 maxiter : int, optional Maximum iterations in finding the solution

Notes

The rate of interest is computed by iteratively solving the (non-linear) equation:

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

for `rate`.

References

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

numpy.nper

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