Asset Depreciation Calculator (Straight-Line)

Asset Depreciation Calculator

Asset Depreciation Formula

Formula

\[ D = \frac{C - S}{L} \\ \\ A_Y = D \times Y \\ \\ B_Y = C - A_Y \]

Where:

$D$ — annual depreciation expense
$C$ — initial asset cost (purchase price)
$S$ — salvage value (estimated residual value at the end of useful life)
$L$ — useful life of the asset in years
$A_Y$ — accumulated depreciation at the end of year $Y$
$B_Y$ — book value at the end of year $Y$

These are the formulas for the straight-line method, which spreads the depreciable cost $(C - S)$ evenly over the asset's useful life. The book value declines by the same amount each year until it reaches the salvage value.

Asset Depreciation – Calculation Example

Example: a company buys equipment for $15,000, expects to sell it for $3,000 after 10 years, and wants to know the depreciation figures for year 5.

\[ D = \frac{15{,}000 - 3{,}000}{10} = 1{,}200 \]

\[ A_5 = 1{,}200 \times 5 = 6{,}000 \]

\[ B_5 = 15{,}000 - 6{,}000 = 9{,}000 \]

Result: the annual depreciation is $1,200, the accumulated depreciation at the end of year 5 is $6,000, and the book value at that point is $9,000.

How to Use the Calculator

Enter the Initial asset cost — the original purchase price of the asset, including installation and delivery costs if they were capitalized.
Enter the Salvage value — the amount you expect to recover when the asset is retired or sold.
Enter the Useful life (years) — the period over which the asset will be used. In the US, this often follows the IRS MACRS class life of the asset.
Enter the Year to calculate — the specific year for which you want the accumulated depreciation and book value.
Read the results: Annual Depreciation, Accumulated Depreciation for the chosen year, and Book Value at End of Year.

If the year you enter exceeds the useful life, the calculator shows an error, because depreciation stops once the book value reaches the salvage value.

What Is Asset Depreciation?

Depreciation is an accounting method that allocates the cost of a tangible asset — such as machinery, vehicles, buildings, or computer equipment — over the years it is used. Rather than recording the full purchase price as an expense in the year of purchase, the cost is spread across the asset's useful life. This matches expenses with the revenues the asset helps generate and gives a more accurate picture of profitability.

Depreciation also reflects physical reality: assets wear out, become obsolete, or lose value through use. Each year, part of the asset's cost is transferred to the income statement as depreciation expense, and the same amount is added to accumulated depreciation on the balance sheet, reducing the asset's book value.

This calculator uses the straight-line method, the simplest and most widely applied depreciation method. It charges an equal amount of depreciation in every year of the asset's life, so the book value declines in a straight, predictable line from the initial cost down to the salvage value. For assets that lose value faster in early years — such as vehicles or technology — the Accelerated Depreciation calculator may be more appropriate.

Interpreting the results is straightforward: the annual depreciation is the expense you record each year; the accumulated depreciation is the total expensed since the asset was put into service; and the book value is what the asset is still worth on your books — roughly, purchase price minus everything expensed so far.

Assumptions, Limitations and Practical Tips

Even usage assumed. Straight-line depreciation suits assets that are used roughly uniformly over time. If usage varies significantly year to year, a units-of-production approach may fit better.
Salvage value matters. Only the difference $C - S$ is depreciated. If the salvage value is hard to estimate, see the Residual Value calculator. Setting salvage value to zero depreciates the entire cost.
Tax rules may differ. For tax purposes, many jurisdictions prescribe specific methods and class lives (for example, MACRS in the US), which may not match straight-line bookkeeping. Always check the rules that apply to your jurisdiction.
Depreciable cost is not market value. Book value is an accounting figure, not necessarily the price the asset would fetch on the market.
Partial years. The calculator assumes full-year depreciation. In practice, conventions such as half-year or mid-month are often applied in the first and last year, which changes the accumulated amounts slightly.

Depreciation affects several other financial figures: it reduces reported profit, lowers the book value of assets on the balance sheet, and influences ratios such as the Return on Capital Employed. If you are tracking the value of goods rather than fixed assets, the Ending Inventory calculator covers the other side of the balance sheet.

Frequently Asked Questions

How do I calculate straight-line depreciation by hand?

Subtract the salvage value from the initial cost to get the depreciable cost, then divide by the useful life in years: $D = \frac{C - S}{L}$. Multiply that annual amount by the number of years elapsed to get accumulated depreciation, and subtract it from the original cost to get the book value. For example, a $20,000 asset with a $2,000 salvage value over 9 years depreciates by $\frac{20{,}000 - 2{,}000}{9} = 2{,}000$ per year.

What is a good depreciation rate for common assets?

Typical useful lives used in accounting are 3–5 years for computers and phones, 5–7 years for vehicles and office furniture, 7–10 years for machinery and equipment, and 25–40 years for buildings. Rates vary by jurisdiction; in the US, tax depreciation follows IRS MACRS class lives, which may differ from the lives used in your financial statements. Check the classification rules that apply to you before choosing a life.

Can the salvage value be higher than the initial cost?

No. If you enter a salvage value greater than the cost, the depreciable cost becomes negative, which makes no accounting sense — an asset cannot appreciate through depreciation. A valid salvage value is zero or a positive amount below the initial cost. If an asset genuinely increases in value (like land or some property), it is not depreciated at all under standard accounting rules.

What is the difference between book value and market value?

Book value is an accounting figure: initial cost minus accumulated depreciation. Market value is what someone would actually pay for the asset today. The two often diverge — a vehicle may sell for more or less than its book value, and real estate frequently exceeds its depreciated book value. When you sell an asset, any difference between the sale price and book value creates a gain or loss on disposal.

Why can't I calculate a year beyond the useful life?

Depreciation stops when the book value reaches the salvage value — the asset is fully depreciated at that point, and no further expense is recorded. Entering year 11 for a 10-year asset would overstate accumulated depreciation. After the useful life ends, the book value simply stays at the salvage value, and the annual depreciation is zero, even if you keep using the asset.

How do I handle an asset bought mid-year?

This calculator assumes full-year depreciation, so a partial first year must be adjusted manually. A common approach is prorating: an asset used for 6 months of its first year gets half the annual depreciation. Tax systems often use conventions instead, such as the half-year convention (always half a year in year one) or the mid-month convention. For a mid-year purchase, multiply the annual amount by the fraction of the year the asset was in service.

Is straight-line depreciation the same as what I use for taxes?

Not necessarily. Many companies use straight-line for financial reporting but an accelerated method for taxes, since systems like MACRS in the US prescribe their own class lives and depreciation schedules. This creates a temporary difference between book and tax depreciation. Keep two sets of figures if you need both, and consult a tax professional for your jurisdiction, as rules vary widely.

Asset Depreciation Converter