Depreciation is how businesses spread the cost of a tangible asset over its useful life. A delivery van, a CNC machine, office computers, and a factory building all lose value over time. Depreciation lets a business record that loss as an expense on the income statement, which reduces taxable income. The One Big Beautiful Bill Act (OBBBA), signed into law on July 4, 2025, restored 100% bonus depreciation for qualified property placed in service after January 19, 2025. This is the biggest change to depreciation rules in years, and it means many businesses can now write off the full cost of equipment in year one.
What This Calculator Does
Enter the asset cost, salvage value, and useful life. 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.
For related business calculations, try our Margin Calculator to analyze profit margins, or our ROI Calculator to evaluate investment returns on depreciating assets.
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 Calculations
Manufacturing Equipment
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.
Company Vehicle
A plumbing business buys a delivery van for $45,000 with an estimated $5,000 residual value after 7 years. Under straight-line, the annual deduction is $5,714. Under DDB, Year 1 produces a $12,857 deduction, which is more than double the straight-line amount. For a profitable business in a high tax bracket, front-loading deductions in Year 1 reduces taxable income when the business is earning the most.
Real-World Scenarios
Small Business Expanding Operations
A printing company in Phoenix buys $120,000 worth of new equipment in March 2025. Under the OBBBA, they can claim 100% bonus depreciation and deduct the entire $120,000 in 2025. Alternatively, they can use Section 179 to expense up to $2,500,000 in 2025 (the limit rises to $2,560,000 for 2026). Either way, the full purchase price reduces taxable income in year one. This calculator helps them compare what the schedule would look like under traditional methods if they prefer to spread deductions instead.
Technology Equipment with Short Lifespan
A marketing agency purchases $40,000 in computers and servers. Tech equipment typically has a 3-year to 5-year useful life and becomes obsolete quickly. Accelerated methods like DDB or SYD front-load larger deductions while the equipment is still in active use, matching the economic reality that such equipment loses value faster in the early years. With 100% bonus depreciation restored in 2025, the agency could also write off the entire $40,000 immediately.
Commercial 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 OBBBA confirmed that Qualified Improvement Property (QIP) maintains its 15-year MACRS life, making it eligible for 100% bonus depreciation. A restaurant owner spending $200,000 on interior renovations can now deduct the full amount in year one rather than spreading it over 15 years. The calculator handles long useful life periods up to 40 years for comparison.
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: The IRS provides standard useful life tables by asset class under MACRS. Using an arbitrarily short life to accelerate deductions may trigger an audit. Always check IRS Publication 946 for the correct recovery period
- 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 on the books
- Overlooking bonus depreciation and Section 179: With 100% bonus depreciation restored for property placed in service after January 19, 2025, many businesses can deduct the full cost immediately. This calculator shows traditional methods, but consult a tax professional to see if immediate expensing is better for your situation
Limitations of This Calculator
This calculator covers three traditional depreciation methods: Straight-Line, Double Declining Balance, and Sum of Years Digits. It does not calculate MACRS depreciation tables, which are the standard for US tax filing. It also does not factor in bonus depreciation under IRC Section 168(k) or Section 179 expensing, both of which can significantly change your actual tax deductions. For tax filing purposes, use IRS Form 4562 and consult a certified public accountant. The calculator is best for comparing methods and understanding how each one affects book value over time.
Authoritative Research and Resources
- IRS: One Big Beautiful Bill Provisions - The official IRS page summarizing the OBBBA tax changes, including the restoration of 100% bonus depreciation for qualified property placed in service after January 19, 2025.
- IRS: Instructions for Form 4562 (2025) - The official instructions for reporting depreciation and amortization, including Section 179 expensing and bonus depreciation elections.
- IRS Publication 946: How to Depreciate Property - The comprehensive IRS guide to depreciation methods, MACRS recovery periods, and special depreciation allowances.