-
numpy.pv(rate, nper, pmt, fv=0.0, when='end')
[source] -
Compute the present value.
- Given:
- Return:
- the value now
Parameters: rate : array_like
Rate of interest (per period)
nper : array_like
Number of compounding periods
pmt : array_like
Payment
fv : array_like, optional
Future value
when : {{?begin?, 1}, {?end?, 0}}, {string, int}, optional
When payments are due (?begin? (1) or ?end? (0))
Returns: out : ndarray, float
Present value of a series of payments or investments.
Notes
The present value is computed by solving the equation:
123fv
+
pv
*
(
1
+
rate)
*
*
nper
+
pmt
*
(
1
+
rate
*
when)
/
rate
*
((
1
+
rate)
*
*
nper
-
1
)
=
0
or, when
rate = 0
:1fv
+
pv
+
pmt
*
nper
=
0
for
pv
, which is then returned.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 present value (e.g., the initial investment) of an investment that needs to total $15692.93 after 10 years of saving $100 every month? Assume the interest rate is 5% (annually) compounded monthly.
12>>> np.pv(
0.05
/
12
,
10
*
12
,
-
100
,
15692.93
)
-
100.00067131625819
By convention, the negative sign represents cash flow out (i.e., money not available today). Thus, to end up with $15,692.93 in 10 years saving $100 a month at 5% annual interest, one?s initial deposit should also be $100.
If any input is array_like,
pv
returns an array of equal shape. Let?s compare different interest rates in the example above:123>>> a
=
np.array((
0.05
,
0.04
,
0.03
))
/
12
>>> np.pv(a,
10
*
12
,
-
100
,
15692.93
)
array([
-
100.00067132
,
-
649.26771385
,
-
1273.78633713
])
So, to end up with the same $15692.93 under the same $100 per month ?savings plan,? for annual interest rates of 4% and 3%, one would need initial investments of $649.27 and $1273.79, respectively.
numpy.pv()

2025-01-10 15:47:30
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