Depreciation Calculator

Straight-line depreciation is the most straightforward method in accounting. It spreads the depreciable cost of an asset evenly over its useful life. The formula is:

Annual Depreciation = (Asset Cost − Salvage Value) / Useful Life

Worked example: Suppose you purchase a piece of equipment for $100,000 with a salvage value of $10,000 and a useful life of 10 years. The annual depreciation expense is ($100,000 − $10,000) / 10 = $9,000 per year. After 10 years, the asset's book value equals its salvage value of $10,000.

Key characteristics:

• Constant annual expense — Every year the income statement shows the same depreciation charge, making earnings smoother and more predictable.
• Linear book value decline — Net book value decreases by the same amount each year, forming a straight line on a chart.
• Widely used for GAAP reporting — Because it's simple and conservative, straight-line is the default choice for most companies' financial statements.

When it makes sense: Straight-line works best for assets that provide consistent economic benefits over time — buildings, leasehold improvements, and general-purpose equipment. If an asset loses most of its value in the first few years (like a car or laptop), an accelerated method better matches expense to usage.

Double declining balance (DDB) is the most common accelerated depreciation method. It charges more depreciation in the early years and less in later years, reflecting the reality that many assets lose value faster when they're new.

How to calculate DDB:

• Step 1: Calculate the depreciation rate: 2 / Useful Life. For a 5-year asset, the rate is 2/5 = 40%.
• Step 2: Each year, multiply the beginning book value by the rate. Note: DDB uses book value, not the depreciable base — salvage value only matters as a floor.
• Step 3: Never depreciate below salvage value. If the calculated depreciation would push book value below salvage, only depreciate down to salvage.
• Step 4 (switchover): At some point, straight-line depreciation on the remaining book value over the remaining life becomes larger than DDB. When that happens, switch to straight-line for the remaining years. This ensures the asset is fully depreciated to salvage value by the end of its life.

Worked example: A $50,000 asset with 5-year life and $5,000 salvage. Rate = 40%. Year 1: $50,000 × 40% = $20,000 (book value drops to $30,000). Year 2: $30,000 × 40% = $12,000 (book value: $18,000). Year 3: the remaining $13,000 depreciable base over 3 remaining years = $4,333 via SL, while DDB gives $18,000 × 40% = $7,200. Since DDB is still higher, continue with DDB. The switchover to straight-line ensures clean full depreciation.

Why DDB matters for valuation: In a DCF model, accelerated depreciation creates larger tax shields in early years. Since those early deductions are worth more in present value terms, accelerated depreciation actually increases the NPV of tax savings compared to straight-line.

Sum-of-years-digits (SYD) is an accelerated depreciation method that falls between straight-line and DDB in terms of how aggressively it front-loads expense. It produces a smoothly declining depreciation schedule.

The formula:

Year t Depreciation = (Remaining Life / SYD) × (Cost − Salvage)

Where SYD = n(n+1)/2, and n is the total useful life in years. For a 5-year asset, SYD = 5(6)/2 = 15. The fractions for each year are 5/15, 4/15, 3/15, 2/15, and 1/15 — and they always sum to 1 (or 100%).

Worked example: A $60,000 asset with 5-year life and $0 salvage. SYD = 15. Year 1: (5/15) × $60,000 = $20,000. Year 2: (4/15) × $60,000 = $16,000. Year 3: $12,000. Year 4: $8,000. Year 5: $4,000. Total = $60,000.

SYD vs. DDB: Both are accelerated, but SYD produces a more predictable, linearly declining pattern. DDB can have an abrupt switchover point when it transitions to straight-line. SYD is often preferred when you want accelerated depreciation with a smoother curve.

Where you'll see SYD: While less common in practice than straight-line or MACRS, SYD appears in academic finance, CPA exam questions, and some international accounting standards. It's a useful benchmark for understanding the spectrum between linear and highly accelerated depreciation.

A depreciation tax shield is the tax savings that result from deducting depreciation expense against taxable income. Since depreciation is a non-cash expense, it reduces taxes without requiring an actual cash outflow in the period — making it one of the most powerful features in corporate finance.

How the tax shield works:

• Tax Shield = Depreciation Expense × Tax Rate— If depreciation is $10,000 and the tax rate is 25%, the company saves $2,500 in taxes that year.
• Total tax savings are the same — Regardless of method, the total depreciation (and total tax savings) over the asset's life is identical. The difference is timing.
• Accelerated methods create more value — A dollar saved in Year 1 is worth more than a dollar saved in Year 10 due to the time value of money. Front-loading depreciation with DDB or SYD creates a higher present value of tax shields.

Impact on DCF models: In a discounted cash flow valuation, free cash flow = Net Income + D&A − CapEx − Changes in Working Capital. The depreciation add-back is a major component of cash flow. When modeling CapEx-heavy businesses (manufacturing, telecom, utilities), getting the D&A schedule right directly affects your FCF projections and therefore your fair value estimate.

Real-world example: The U.S. Tax Cuts and Jobs Act of 2017 allowed 100% bonus depreciation (expensing the full cost in Year 1), creating an enormous upfront tax shield. This accelerated depreciation provision significantly boosted after-tax cash flows for capital-intensive companies.

Companies often maintain two sets of depreciation schedules — one for financial reporting (book) and one for tax purposes. They serve different goals, and understanding the difference is essential for accurate financial analysis.

Book depreciation (GAAP/IFRS):

• Used for financial statements reported to investors and regulators
• Most companies use straight-line to produce smooth, predictable earnings
• Useful life and salvage value are estimated by management based on the asset's expected economic life
• Appears on the income statement as part of operating expenses and on the balance sheet as accumulated depreciation

Tax depreciation (MACRS in the U.S.):

• Used to calculate taxable income on the company's tax return
• The IRS mandates MACRS (Modified Accelerated Cost Recovery System), which uses prescribed recovery periods and accelerated rates
• Salvage value is typically assumed to be zero for tax purposes
• Often results in higher depreciation expense in early years and lower in later years compared to book depreciation

The timing difference creates deferred taxes: When tax depreciation exceeds book depreciation in early years, the company pays less tax now but will pay more later. This creates a deferred tax liability on the balance sheet. For financial modeling, you need to track this difference to accurately project cash taxes versus book taxes.

For DCF modeling: Use the tax depreciation schedule (or a reasonable approximation) to calculate actual cash taxes, since that determines real cash outflows. The book depreciation schedule drives the income statement presentation but doesn't reflect true cash flow timing.

Depreciation plays a dual role in free cash flow calculation, and understanding this is critical for building accurate DCF models.

The depreciation cycle in a DCF:

• Income Statement: Depreciation reduces operating income (EBIT) and therefore net income. It's an expense that lowers reported earnings.
• Cash Flow Statement: Depreciation is added back to net income in the operating section because it's a non-cash charge. The cash was spent when the asset was purchased (CapEx), not when it's depreciated.
• Free Cash Flow: FCF = Net Income + D&A − CapEx ± Changes in Working Capital. D&A gets added back, but CapEx gets subtracted. For a company in steady state, D&A roughly equals maintenance CapEx, and they approximately cancel out.
• Tax Shield: Even though D&A is added back, it already reduced taxable income, generating real cash savings. This tax shield is embedded in the lower tax payment within net income.

Why the D&A-to-CapEx ratio matters: If D&A significantly exceeds CapEx, the company may be under-investing (harvesting its asset base). If CapEx significantly exceeds D&A, the company is investing heavily in growth. Both scenarios have valuation implications — the first may signal declining future revenues, while the second may signal future cash flow growth.

Modeling tip: In the projection period of a DCF, many analysts tie depreciation to a percentage of revenue or a percentage of gross PP&E (property, plant, and equipment). For the terminal period, D&A should roughly equal maintenance CapEx to reflect a sustainable steady state.

Accumulated depreciation is the total depreciation expense that has been recorded against an asset since it was placed in service. It's a contra asset account on the balance sheet — it reduces the gross value of the asset to show its net book value (also called carrying value).

The balance sheet relationship:

Net Book Value = Gross Asset Cost − Accumulated Depreciation

• Year 0: You buy equipment for $100,000. Balance sheet shows: Gross PP&E $100,000, Accumulated Depreciation $0, Net Book Value $100,000.
• Year 3 (straight-line, 10-year life, $10K salvage): Annual depreciation = $9,000. After 3 years: Gross PP&E $100,000, Accumulated Depreciation $27,000, Net Book Value $73,000.
• End of life (Year 10): Accumulated Depreciation = $90,000, Net Book Value = $10,000 (the salvage value).

What accumulated depreciation tells you: A high ratio of accumulated depreciation to gross PP&E suggests the company's assets are aging and may need replacement soon. This is a useful indicator when forecasting future CapEx needs in a valuation model. An "asset age ratio" of 70%+ often signals significant reinvestment needs ahead.

Important distinction: Net book value is an accounting number, not market value. A building purchased for $1M with $800K accumulated depreciation has a book value of $200K but might be worth $2M on the open market. When analyzing asset-heavy companies, always consider whether book values are a reasonable proxy for economic value.