numpy.nper¶

numpy.nper(rate,pmt,pv,fv=0,when='end')[source]¶

Compute the number of periodic payments.

decimal.Decimal type is not supported.

Parameters:	rate:array_like Rate of interest (per period) pmt:array_like Payment pv:array_like Present value fv:array_like, optional Future value when:{{‘begin’, 1}, {‘end’, 0}}, {string, int}, optional When payments are due (‘begin’ (1) or ‘end’ (0))

Notes

The number of periodsnper is computed by solving the equation:

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

but ifrate=0 then:

fv+pv+pmt*nper=0

Examples

If you only had $150/month to pay towards the loan, how long would it taketo pay-off a loan of $8,000 at 7% annual interest?

>>>print(round(np.nper(0.07/12,-150,8000),5))64.07335

So, over 64 months would be required to pay off the loan.

The same analysis could be done with several different interest ratesand/or payments and/or total amounts to produce an entire table.

>>>np.nper(*(np.ogrid[0.07/12:0.08/12:0.01/12,...-150:-99:50,...8000:9001:1000]))array([[[  64.07334877,   74.06368256],        [ 108.07548412,  127.99022654]],       [[  66.12443902,   76.87897353],        [ 114.70165583,  137.90124779]]])