Straight Line Depreciation

How to Calculate Straight Line Depreciation (Step-by-Step)

The straight line depreciation methodology is characterized by the reduction in the carrying value of a fixed asset based on assumptions regarding the following variables:

1. Purchase Cost: The initial cost of purchasing the fixed asset, i.e. the capital expenditure (Capex)
2. Useful Life: The number of years in which the fixed asset is anticipated to offer economic benefits
3. Salvage Value (“Scrap Value”): The residual value of the fixed asset at the end of its useful life

Taking a step back, the concept of depreciation in accounting stems from the purchase of PP&E – i.e. capital expenditures (Capex).

Further, depreciation can be thought of as the gradual decline in value of a fixed asset (i.e. property, plant & equipment) over its useful life, which is the estimated duration that the asset is expected to provide economic benefits.

Under the matching principle in accrual accounting, the costs associated with an asset with long-term benefits must be recognized in the same period for consistency.

Hence, the depreciation line item – which is typically embedded within either cost of goods sold (COGS) or operating expenses (OpEx) – is a non-cash expense, as the real cash outflow occurred earlier when the Capex was spent.

There are a couple of accounting approaches for calculating depreciation, but the most common one is straight-line depreciation.

Straight Line Depreciation Formula

In the straight line method of depreciation, the value of an asset is reduced in equal installments in each period until the end of its useful life.

The formula consists of dividing the difference between the initial CapEx amount and the anticipated salvage value at the end of its useful life by the total useful life assumption.

Typically, the salvage value (i.e. the residual value that that asset could be sold for) at the end of the asset’s useful life is assumed to be zero.