depreciationDb¶

Evaluates the depreciation of an asset using the fixed-declining balance method.

Synopsis¶

depreciationDb (cost, salvage, life, period, month)

Required Arguments¶

float cost (Input): Initial value of the asset.
float salvage (Input): The value of an asset at the end of its depreciation period.
int life (Input): Number of periods over which the asset is being depreciated.
int period (Input): Period for which the depreciation is to be computed. period cannot be less than or equal to 0, and cannot be greater than life +1.
int month (Input): Number of months in the first year. month cannot be greater than 12 or less than 1.

Return Value¶

The depreciation of an asset for a specified period using the fixed-declining balance method. If no result can be computed, NaN is returned.

Description¶

Function depreciationDb computes the depreciation of an asset for a specified period using the fixed-declining balance method. Routine depreciationDb varies depending on the specified value for the argument period, see table below.

period	Formula
period = 1	\[\mathrm{cost} \times \mathrm{rate} \times \frac{\mathrm{month}}{12}\]
period = life	\[(\mathrm{cost} - \text{total depreciation from periods}) \times \mathrm{rate} \times \frac{12 - \mathrm{month}}{12}\]
period other than 1 or life	\[(\mathrm{cost} - \text{total depreciation from prior periods}) \times \mathit{rate}\]

where

\[\mathit{rate} = 1 - \left(\frac{\mathrm{salvage}}{\mathrm{cost}}\right)^ {\left(\frac{1}{\mathit{life}}\right)}\]

NOTE: rate is rounded to three decimal places.

Example¶

In this example, depreciationDb computes the depreciation of an asset, which costs $2,500 initially, a useful life of 3 periods and a salvage value of $500, for each period.

from __future__ import print_function
from numpy import *
from pyimsl.math.depreciationDb import depreciationDb

cost = 2500
salvage = 500
life = 3
month = 6

for period in range(1, life + 2):
    db = depreciationDb(cost, salvage, life, period, month)
    print("For period %i, db = $%.2f." % (period, db))

Output¶

For period 1, db = $518.75.
For period 2, db = $822.22.
For period 3, db = $481.00.
For period 4, db = $140.69.