What Is Depreciation?
Depreciation is the systematic reduction in the recorded value of a tangible asset over its useful life. Businesses depreciate assets such as machinery, vehicles, computers, and buildings to reflect that these items wear out, become obsolete, or lose value over time. Depreciation is recorded as an expense on the income statement, reducing taxable income and aligning the cost of an asset with the revenue it helps generate.
Choosing the right depreciation method affects financial statements, tax liability, and the reported profitability of a business in any given year. This calculator supports the three most widely used methods so you can compare them side by side.
What This Calculator Does
Enter the asset cost, salvage value, and useful life, then select a depreciation method. The calculator produces the annual depreciation amount, a year-by-year schedule, and a chart comparing the book value trajectory under all three methods simultaneously.
Inputs Required
- Asset Cost: The original purchase price or cost basis of the asset
- Salvage Value: The estimated residual value of the asset at the end of its useful life
- Useful Life: The number of years over which the asset will be depreciated
- Depreciation Method: Straight-Line (SL), Double Declining Balance (DDB), or Sum of Years Digits (SYD)
Outputs Provided
- Year 1 Depreciation: The deduction amount in the first year under the selected method
- Annual Rate: The effective depreciation rate per year
- Depreciation Schedule: A full year-by-year table of depreciation and book value
- Book Value Chart: A comparison of all three methods over the asset's full life
How the Calculation Works
Straight-Line Method (SL)
The simplest method. The same amount is deducted every year for the full useful life of the asset.
Annual Depreciation = (Asset Cost - Salvage Value) / Useful Life
A $50,000 machine with a $5,000 salvage value and 10-year life depreciates by $4,500 per year under this method.
Double Declining Balance Method (DDB)
An accelerated method that applies twice the straight-line rate to the declining book value each year. Higher deductions occur early; they taper off over time. The depreciation cannot reduce the book value below the salvage value.
DDB Rate = 2 / Useful Life
Annual Depreciation = Book Value x DDB Rate
(Cannot reduce Book Value below Salvage Value)
Sum of Years Digits Method (SYD)
Another accelerated method. Each year's depreciation fraction is based on the remaining useful life divided by the sum of all years in the asset's life.
Sum of Years = n x (n + 1) / 2
Year k Depreciation = (n - k + 1) / Sum of Years x Depreciable Base
For a 5-year asset: Sum = 15. Year 1 fraction = 5/15, Year 2 = 4/15, and so on
How to Use the Calculator
- Enter the original purchase cost of the asset
- Enter the estimated salvage value at end of life (enter 0 if none)
- Set the useful life in years using the slider or preset buttons
- Select your preferred depreciation method
- View the Year 1 depreciation, the full schedule table, and the book value comparison chart
Example Calculation
A company purchases equipment for $30,000 with a $3,000 salvage value and a 5-year useful life. Depreciable base = $27,000.
- Straight-Line: $27,000 / 5 = $5,400/year every year
- Double Declining (Year 1): $30,000 x 40% = $12,000; Year 2: $18,000 x 40% = $7,200; declining further each year
- Sum of Years (Year 1): 5/15 x $27,000 = $9,000; Year 2: 4/15 x $27,000 = $7,200
The total depreciation over 5 years is identical for all three methods at $27,000. The methods differ only in timing, which affects annual tax deductions and reported profits.
Real World Scenarios
Depreciating a Company Vehicle
A business purchases a delivery van for $45,000 with an estimated $5,000 residual value after 7 years. Using straight-line depreciation, the annual deduction is $5,714. Under double declining balance, Year 1 produces a $12,857 deduction, significantly reducing taxable income early on.
Technology Equipment
Computers and tech equipment typically have a 3-year to 5-year useful life and become obsolete quickly. Accelerated methods like DDB or SYD front-load larger deductions while the asset is still in active use, matching the economic reality that such equipment loses value faster in the early years.
Building Improvements
Commercial building improvements are often depreciated over 15 to 39 years using the straight-line method, as buildings retain value more consistently over time. The calculator handles long useful life periods up to 40 years.
Why This Calculation Matters
Depreciation directly affects taxable income, cash flow planning, and the accuracy of a company's balance sheet. Choosing the right method can front-load deductions during high-income years or smooth them out to stabilize reported profits. For small business owners, understanding depreciation is essential for accurate financial reporting and tax planning.
Common Mistakes to Avoid
- Ignoring the salvage value: Depreciation stops when book value reaches the salvage value. Depreciating below salvage overstates the expense and misrepresents the asset's value
- Applying the wrong useful life: Tax authorities provide standard useful life tables by asset class. Using an arbitrarily short life to accelerate deductions may trigger an audit
- Confusing depreciation with cash outflow: Depreciation is a non-cash accounting expense. The cash was spent when the asset was purchased. Depreciation simply allocates that cost over time
- Using the same method for all assets: Different asset types may benefit from different methods. Consult a tax professional to select the most advantageous method for each asset class in your business