Asset depreciation,
three methods compared.

Field guide

How asset depreciation works and why the method matters.

Depreciation is the systematic allocation of an asset's cost over its useful life. When a company buys equipment, a vehicle, or a building, it doesn't expense the full cost on day one. Instead, it spreads the cost, minus whatever the asset is expected to be worth at the end of its life — across the years it will be used. This produces a more accurate picture of profit and more accurately matches expenses to the revenue the asset helps generate.

For business owners, accountants, and investors, the choice of depreciation method has real consequences: it affects net income, taxable income, balance-sheet asset values, and cash-flow timing. Understanding all three main methods and when each is appropriate — is fundamental to financial literacy.

The depreciable base

Before any method is applied, you need the depreciable base: the amount the asset actually loses in value over its lifetime. This is simply:

The salvage value (also called residual value or scrap value) is the estimated market value of the asset at the end of its useful life. A $50,000 delivery van expected to be worth $5,000 in five years has a depreciable base of $45,000. All three methods calculate deductions against this same $45,000 — they simply distribute it differently across the years.

Method 1: Straight-Line (SL)

The simplest and most widely used method. Every year of the asset's life receives the exact same deduction. For the $45,000 van over five years: $45,000 ÷ 5 = $9,000/yr. The book value declines in a perfectly straight line from cost to salvage.

Best for: assets that deliver uniform value year over year — buildings, furniture, certain equipment, and intangible assets. Also the default method for IFRS (International Financial Reporting Standards) and for many financial reporting purposes where simplicity and comparability matter.

Method 2: Double Declining Balance (DDB)

An accelerated method that front-loads deductions: you claim the most depreciation in the early years of the asset's life and progressively less as years pass. For the $50,000 van with a 5-year life:

• Rate = 2 ÷ 5 = 40% per year
• Year 1: $50,000 × 40% = $20,000
• Year 2: $30,000 × 40% = $12,000
• Year 3: $18,000 × 40% = $7,200
• Year 4–5: automatically switches to straight-line to fully depreciate to salvage

The SL switchover is required by GAAP: once the remaining straight-line amount would produce a higher deduction than the declining balance formula, the calculator automatically switches. This ensures the asset always reaches exactly its salvage value by the last year.

Best for: assets that lose value quickly in the early years — technology equipment, computers, vehicles with high early-year usage. Also the basis for several MACRS classes in U.S. tax depreciation.

Method 3: Sum-of-Years' Digits (SYD)

A second accelerated method that produces a smoother, more linearly declining curve than DDB. For a 5-year asset, the sum of digits is 1+2+3+4+5 = 15. Fractions assigned to each year, from first to last: 5/15, 4/15, 3/15, 2/15, 1/15. Applied to the $45,000 base:

• Year 1: 5/15 × $45,000 = $15,000
• Year 2: 4/15 × $45,000 = $12,000
• Year 3: 3/15 × $45,000 = $9,000
• Year 4: 2/15 × $45,000 = $6,000
• Year 5: 1/15 × $45,000 = $3,000

Unlike DDB, SYD never requires a switchover, the formula naturally terminates at salvage value without capping logic. The deductions decline by a constant dollar amount each year (for a constant base), making the schedule predictable and easy to explain to stakeholders.

Best for: assets with moderately accelerated obsolescence or wear, where the most-even taper of DDB is slightly too aggressive. Less common in practice than SL or DDB but occasionally required by specific accounting standards or industries.

Comparing the three methods: the key differences

All three methods produce the same lifetime total deduction , the depreciable base. The method only changes how deductions are distributed across years, not the total amount claimed.

MACRS: the U.S. tax depreciation system

For U.S. federal income tax purposes, most businesses use MACRS (Modified Accelerated Cost Recovery System), which is prescribed by the IRS and differs from GAAP accounting methods in important ways:

• Asset classes with prescribed recovery periods . MACRS assigns each asset type to a class (3-year, 5-year, 7-year, 10-year, 15-year, 20-year, 27.5-year residential, 39-year nonresidential). Computers are 5-year property; office furniture is 7-year; most equipment is 5- or 7-year.
• Half-year and mid-quarter conventions: MACRS assumes assets are placed in service at the midpoint of the year (or quarter), producing a smaller first-year deduction than a full-year DDB calculation would.
• Section 179 and Bonus Depreciation: businesses can elect to immediately expense qualifying assets (Section 179, up to $1.22M in 2024) or claim 60% bonus first-year depreciation on most new property in 2024.

MACRS tables are published in IRS Publication 946. This calculator uses the three GAAP-standard methods above rather than MACRS, which is better suited to financial planning and accounting reporting.

Which method should you use?

The choice depends on your purpose:

• Financial reporting (GAAP/IFRS): straight-line is the default for most assets unless there is clear evidence that economic benefits are consumed more rapidly in early years. The auditor and standards body have the final word.
• Tax minimization: accelerated methods (DDB, SYD, MACRS, bonus depreciation) defer tax liability by producing higher early-year deductions. This is generally advantageous when the time value of money is factored in.
• Internal management reporting: use whichever method best reflects how the asset is actually consumed. A vehicle driven heavily in its early years warrants an accelerated method or even units-of-production depreciation.

Note that companies often use different methods for financial reporting and tax purposes. This creates a deferred tax liability (or asset) on the balance sheet, which is reported in accordance with ASC 740 or IAS 12.

Depreciation vs. amortization

Depreciation applies to tangible assets with a physical form: equipment, vehicles, buildings, machinery. Amortization applies to intangibleassets: patents, copyrights, trademarks, software licenses, goodwill. The math is the same (straight-line is overwhelmingly standard for intangibles), but the terminology and balance sheet presentation differ. Both are non-cash charges — the asset was purchased in a prior period; the depreciation/amortization expense reduces income without reducing cash in the current period.

Is depreciation a cash expense?

No. Depreciation is a non-cash charge that reduces accounting net income but does not require a cash payment in the period it's recorded. The cash left the business when the asset was purchased. This is why depreciation is added back in the operating activities section of the cash flow statement: it reduced net income but didn't actually consume cash.

Understanding this distinction is critical for valuation: EBITDA (Earnings Before Interest, Taxes, Depreciation, and Amortization) strips out D&A to approximate operating cash generation before capital allocation decisions.

Disclaimer

This calculator models the three most common GAAP depreciation methods for planning and educational purposes. For actual tax filings, consult IRS Publication 946 and a qualified tax adviser. For financial reporting, apply the methods as prescribed by the applicable accounting standard (ASC 360 for U.S. GAAP, IAS 16 for IFRS) and verify with your auditor.