Formulas for Depreciation

The calculation of depreciation is based on several pieces of information, some of which have to be calculated themselves: depreciable base, useful life, and apportionment method.

If Mass Depreciation # Disposed Units Ratio = 1

Else # Disposed Units Ratio = Disposed Units / Total Units

# Disposed Units Ratio * Calculated Depreciation

Incremental Depreciation = Incremental Fraction * Depreciation

If Historical Cost - Salvage Value - old Accumulated Depreciation – ‘new’ Deprecation < $0.00

Then the amount of Depreciation should be set to the amount that makes Historical Cost - Salvage Value - old Accumulated Depreciation - 'rounded down' Deprecation = $0.00.

Else ‘new’ Depreciation will be used

The Incremental Fraction is a ratio of days eligible for depreciation in a given calendar year divided by the total number of days in that calendar year.

End Date – Start Date / # days in calendar year

When the days eligible for depreciation span a calendar year (December 31st), then there are two partial ranges in a single depreciation time frame. When there is a Depreciation Elements Change (DEPEC) record for an asset that depreciates with time (not activity), there can be two or more ranges.

When there are multiple ranges of depreciation, the very last range adds 1 day to the calculation, which is a result of previous ranges not using the last day in the range. That same 1 day is also added in cases where a range should include the last day of the range. The first such situation is when a sale, transfer, or disposal occurs before the first depreciation. The next is when depreciation occurs for the first time yet the depreciation period does not span the end of a calendar year.

 

Where there is only a single range, the calculation can be any of the following:

End Date

Start Date

Depreciation End Date

Acquisition Date

Disposal Date

In Service Date

Sale Date

Last Depreciation Date

Transfer Date

 

 

When the first range in a series of ranges, the calculation can be any of the following:

End Date

Start Date

Calendar Year End Date

Acquisition Date

DEPEC’s Effective Date

In Service Date

Sale Date

Last Depreciation Date

Transfer Date

 

Disposal Date

 

 

When a second or subsequent range in a series, the calculation can be any of the following:

End Date

Start Date

Depreciation End Date

Calendar Year Begin Date

DEPEC’s Effective Date

DEPEC’s Effective Date

Sale Date

 

Transfer Date

 

Disposal Date

 

 

When validating calculated depreciation, there are two points to consider in the following formula:

End Date – Start Date / # days in calendar year

Straight Line Calculation

Declining Balance Calculation

Sum-of-the-Years’-Digits Calculation