numpy.rate¶

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

Compute the rate of interest per period.

Deprecated since version 1.18: rate is deprecated; for details, see NEP 32 [1]. Use the corresponding function in the numpy-financial library, https://pypi.org/project/numpy-financial.

Parameters

nperarray_like: Number of compounding periods
pmtarray_like: Payment
pvarray_like: Present value
fvarray_like: Future value
when{{‘begin’, 1}, {‘end’, 0}}, {string, int}, optional: When payments are due (‘begin’ (1) or ‘end’ (0))
guessNumber, optional: Starting guess for solving the rate of interest, default 0.1
tolNumber, optional: Required tolerance for the solution, default 1e-6
maxiterint, 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

1: NumPy Enhancement Proposal (NEP) 32, https://numpy.org/neps/nep-0032-remove-financial-functions.html
2: 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