Depreciation

Depreciation is the accounting method of allocating the cost of a tangible asset, such as machinery, vehicles, or buildings, over its useful life rather than expensing the full purchase cost in the year it was bought. This matching of cost to the periods an asset actually helps generate revenue is a core principle of accrual accounting.

Why assets are depreciated rather than expensed

If a company bought a delivery truck and expensed its entire cost in one year, that year’s income statement would show an artificially large expense while later years, when the truck is still generating revenue, would show none of its cost. Depreciation spreads the expense across the years the asset is actually in use, giving a more accurate picture of profitability in each period.

Straight-line depreciation

The simplest and most widely used method is straight-line depreciation, which divides an asset’s depreciable cost, its purchase price minus estimated salvage value, evenly across its useful life. A machine costing $50,000 with a $5,000 salvage value and a 10-year life would depreciate by $4,500 per year under this method, producing a predictable, consistent expense.

Accelerated methods and MACRS

Other methods front-load depreciation, recognizing larger deductions in earlier years. In the United States, the Modified Accelerated Cost Recovery System (MACRS), introduced by the Tax Reform Act of 1986 as a successor to the earlier Accelerated Cost Recovery System, is the required method for most tax depreciation. MACRS uses declining-balance rates, commonly 200 percent for shorter-lived property, before switching to straight-line once that produces a larger deduction.

Book depreciation versus tax depreciation

Companies often use straight-line depreciation for their financial statements, since it is simple and produces smooth, predictable expenses for investors to analyze, while using MACRS for tax filings to accelerate deductions and reduce taxable income sooner. This creates a temporary difference between book and tax income that accountants track separately.

Units of production and other methods

Beyond straight-line and declining-balance approaches, some companies use the units-of-production method, which ties depreciation to actual usage, such as machine hours or units manufactured, rather than the passage of time. This method suits assets like factory equipment, where wear depends more on how heavily the asset is used than on how many years have passed since purchase.

Accumulated depreciation on the balance sheet

Depreciation expense recorded each period accumulates on the balance sheet in a contra-asset account called accumulated depreciation, which reduces the asset’s reported book value over time. An asset’s original cost minus its accumulated depreciation equals its net book value, a figure that approaches the asset’s estimated salvage value by the end of its useful life.

Depreciation’s effect on taxes and cash flow

Although depreciation does not involve a direct cash outlay in the period it is recorded, it still reduces taxable income, which lowers the actual cash a company pays in taxes. This is why depreciation is added back to net income when preparing the indirect-method cash flow statement, reversing its non-cash effect while preserving the real tax savings it generated.

Depreciation for intangible assets: amortization

Tangible assets are depreciated, but intangible assets with a finite useful life, such as patents or purchased customer contracts, go through an analogous process called amortization. The underlying logic is identical, spreading an asset’s cost over the periods it benefits, but accountants use the separate term to distinguish intangible assets from the physical property and equipment that depreciation covers.

Impairment versus depreciation

Depreciation follows a predictable schedule set at the time an asset is acquired, but if an asset’s value drops suddenly and significantly, due to damage, obsolescence, or a changed market, accountants may need to record an impairment charge separately, writing the asset down to its new, lower recoverable value outside the normal depreciation schedule.

Depreciation and asset replacement planning

Finance teams use depreciation schedules not only for accounting purposes but also for planning when major equipment will likely need replacement, since an asset nearing the end of its depreciation schedule is often approaching the end of its practical useful life as well. This planning helps companies budget capital expenditures well in advance rather than being caught off guard by sudden equipment failures.

International differences in depreciation rules

Depreciation rules vary meaningfully between tax jurisdictions. While the United States uses MACRS for tax purposes, other countries apply their own government-set depreciation schedules and allowances, meaning a multinational company often maintains several different depreciation calculations for the same physical asset depending on which country’s tax return is being prepared.

Component depreciation

For complex assets made of parts with different useful lives, such as an airplane with an engine that must be replaced far sooner than the airframe, some accounting standards require component depreciation, splitting the asset into separate parts each depreciated on its own schedule rather than treating the whole asset as a single uniform item.

Fully depreciated assets still in use

An asset can remain fully depreciated on the books, carrying zero remaining book value, while still functioning and generating revenue for the business, since depreciation schedules are accounting estimates rather than precise predictions of when equipment will physically stop working.

FAQs

Is depreciation a cash expense?

No, depreciation is a non-cash expense; it reduces reported net income on the income statement but does not involve any actual cash leaving the company in that period.

Why might a company use different depreciation methods for its books and its tax return?

To present smooth, predictable expenses to investors while legally minimizing and deferring tax payments through faster deductions allowed under tax rules like MACRS.

Editorially reviewed by Specialty Digest Editorial TeamLast reviewed November 1, 2026Researched and drafted with AI assistanceReport an issue