Sum of the Years' Digits Accelerated Depreciation Method

Sum of the Years' Digits Accelerated Depreciation Methdology
••• Joshua Kennon

Many companies calculate their depreciation expense using an accounting method called accelerated depreciation. In this depreciation scenario, an asset, such as a piece of equipment, has its book value reduced on the balance sheet at a faster rate than a traditional straight-line depreciation method. Companies use a few different methods for achieving this, such as the Sum of Years' Digits (SYD) method.

Reasons to Accelerate Depreciation

Accelerated depreciation methods allow for greater depreciation expense deductions in the earlier years of the equipment or other asset's life. Companies typically use this method to minimize their taxable income. Accelerated depreciation methods could als be seen as more accurate, as they assume that an asset loses a majority of its value in the first few years of its use.

Calculating Sum of the Years' Digits Depreciation

To calculate depreciation charges using the sum of the years' digits method, you'll need to first get the depreciable base, which is the cost of the asset.

Next, you'll calculate the salvage value of the asset. This calculation works the same for both the SYD and straight-line depreciation methods.  For example, if you buy an asset for $100,000 and it can be sold for an estimated $10,000 at the end of its useful life, the balance subject to depreciation is $90,000 and the salvage value is $10,000.

For the following example, the cost of the asset is $25,000 with zero salvage value for simplification. The asset has a depreciable life of five years.

Calculate the "applicable percentage" of depreciation for each year of the asset's life. To do this under the sum of the years' digits method, you can use either of the following methods.

Take the expected life of an asset in years, count backward to one, then add the figures together.  For example, for an asset with five years of estimated useful life, you would perform the following calculation:

5 years useful life = 5 + 4 + 3 + 2 + 1

SYD  = 15

Alternatively, you can use the following equation to calculate the applicable percentage:

SYD = depreciable life * (depreciable life + 1) / 2

Using our current example, this would become:

SYD = 5 * (5+1) / 2 = 15

The Formula in Action

Using the information from the ezmple above, you would calculate the applicable depreciation percentage for each depreciable year.  In the first year, the asset value subject to depreciation would be expensed 5/15 in value (the fraction 5/15 is equal to 33.33% of the asset's value).  In the second year, the asset value subject to depreciation would be expensed 4/15 (26.67%).  In the third year, the asset value subject to depreciation would be expensed 3/15 (20.00%).  This would continue until the asset was fully depreciated, having been completely expensed on the income statement and fully depreciated on the balance sheet.  

To show the example in table format, the SYD depreciation expense for the life of this asset would be as follows:

Example Depreciation Calculation Using Sum of the Years' Digits Depreciation Method
YearSYD FractionApplicable Percentage Depreciation RateAnnual Depreciation Expense on Income StatementRemaining Depreciation BaseSalvage Value


The same asset, using straight-line depreciation and zero salvage value, would be depreciated at ($25,000/5) or $5,000 per year for five years until the asset depreciates to zero value.

The same company, with the exact same assets, would appear to be earning different amounts of profit, and have assets carried at different values on the balance sheet, depending upon which depreciation method was utilized. In both cases, the economic reality is the same.