### ZIMSEC O Level Principles of Accounts Notes: The reducing balance/diminishing balance method

• As discussed in this topic there are number of ways in which depreciation can be calculated
• The reducing balance method is one of these methods
• It is also known as the diminishing balance method
• A fixed percentage is deducted from the first from cost then subsequently from the net book value of the asset each period
• The result is that the amount of depreciation for the asset decreases each year
• Consider the example shown below of a lorry bought for 10 000 and depreciated at a rate of 20% each year over 4 years
YearDepreciation for the yearNet Book Value/Cost of asset
120008000
216006400
312805120
410244096
• As you can see the depreciation cost for each year drecreases
• This is likely to be more indicative of certain assets whose maintenance cost is low in the early years but increases with time
• The following formula is used to find out the percentage to be used:
• $r=1-\sqrt[n]{\frac{s}{c}}$
• Where:
• n is the estimated useful life in years
• s is the net residual value (this must be a significant amount or the answers will be absurd, since the depreciation rate would amount to nearly one)
• c is the cost of the asset
• r  is  the resultant rate of depreciation to be applied
• For example given that the useful life of an asset is 4 years, its cost $10 000 and residual value$256
• The rate of depreciation would be:
• $r=1-\sqrt{\frac{256}{10000}}$
• 0.6
• That is 60%

• It is easy to understand and implement
• Equalizes the burden of costs on the Income Statement by balancing maintenance costs and depreciation
• It is acceptable by tax authorities and widely recognised
• Matches cost of revenue for each period
• Can be used on short term assets that are susceptible to technology changes by writing off larger amounts in the early years