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Straight-Line Depreciation Calculator

Calculate annual depreciation evenly over an asset's useful life.

About this calculator

This calculator spreads an asset's depreciable value evenly across every year of its useful life, the simplest of the standard depreciation methods. Annual Depreciation is the depreciable base -- cost minus salvage value (line 9) -- divided by useful life (line 10), and that same dollar figure repeats identically every year up through useful life (line 16), which is what makes it "straight-line" rather than accelerated. Asset cost has the largest effect on annual depreciation, current-year depreciation, and accumulated depreciation, since it drives the depreciable base directly; useful life has a smaller but still substantial effect (it's in the denominator); salvage value's effect is smaller still, since it only reduces the depreciable base by its own amount rather than scaling the whole calculation. Book value follows that same cost-driven pattern while the asset is still being depreciated, but once you select a year beyond useful life, book value equals salvage value exactly, regardless of cost.

Depreciation Rate is different: it's driven mainly by useful life, because expressing annual depreciation as a percentage of cost cancels out most of cost's own influence, leaving 1/usefulLife as the dominant term. Selecting a later year raises Accumulated Depreciation (more years' worth of the same flat amount) but does not change Annual Depreciation itself, which is fixed for the life of the asset once cost, salvage value, and useful life are set. This model does not apply IRS depreciation conventions like MACRS's half-year rule or mid-quarter switching.

Inputs

$
$
years

Results

Annual Depreciation

$4,500.00

Current Year Depreciation$4,500.00
Accumulated Depreciation$4,500.00
Book Value$45,500.00
Depreciation Rate9%
How to Use This Calculator
  1. Enter the asset's purchase cost.
  2. Input the estimated salvage value at end of useful life.
  3. Set the useful life in years.
  4. Select the year you want to view.
  5. Review the annual depreciation expense (constant each year) and cumulative accumulated depreciation.

How the result changes with Asset Cost

Asset CostAnnual Depreciation
$25,000.00$2,000.00
$37,500.00$3,250.00
$75,000.00$7,000.00
$125,000.00$12,000.00

What each input means

Asset Cost
Original purchase price of the asset.
Salvage Value
Estimated residual value at end of useful life.
Useful Life
Expected useful life of the asset in years.
Current Year
Year of depreciation to view.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Asset Cost = 50000, Salvage Value = 5000, Useful Life = 10, Current Year = 1 = 4 input(s) provided
  2. Calculate Annual Depreciation
    Annual Depreciation
    4500 = $4,500
  3. Calculate Current Year Depreciation
    4500 = $4,500
  4. Calculate Accumulated Depreciation
    Accumulated Depreciation
    4500 = $4,500

Engine last updated . Checked against 1 independently-derived test — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.

Frequently Asked Questions

Why does asset cost affect the result more than useful life does?

Annual Depreciation is (assetCost - salvageValue) / usefulLife (line 9-10). Cost moves the numerator directly and by its full amount, while salvage value only partly offsets that numerator, and useful life sits in the denominator, whose effect is real but proportionally smaller at the default 10-year life. Cost's larger share of the formula's structure is what gives it the bigger swing.

Does selecting a later year change my Annual Depreciation figure?

No. Annual Depreciation is a constant, computed once from cost, salvage value, and useful life (line 9-10) -- it's the same dollar amount whether you're viewing year 1 or year 9. Selecting a later year instead raises Accumulated Depreciation, which multiplies that fixed annual amount by however many years (up to useful life) you've selected (line 12-13).

Why is Depreciation Rate driven mostly by useful life, not cost?

Depreciation Rate expresses annual depreciation as a percentage of cost (annualDepreciation / cost * 100, line 15). Since annual depreciation is itself roughly proportional to cost (cost minus a comparatively small salvage value, divided by useful life), dividing by cost again cancels out most of cost's influence on the rate, leaving 1 / usefulLife as by far the biggest driver of the percentage.

What happens once I select a year past the asset's useful life?

Current Year Depreciation drops to zero once the selected year exceeds useful life (line 16, year <= usefulLife ? annualDepreciation : 0), reflecting that a fully depreciated asset has no further expense to record. Book Value, meanwhile, is floored at salvage value (line 14) and never drops below it, matching the real accounting rule that an asset shouldn't be depreciated past its residual worth.

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