Accounting for fixed asset additions means putting the full acquisition cost on the balance sheet, then spreading that cost across the asset’s useful life through depreciation. The judgment calls sit at the front end: deciding whether a cost is a capital improvement or a current expense, pulling every dollar that belongs into the cost basis, and then choosing the right depreciation treatment for books and for taxes. Get those decisions right and the mechanics are simple. Get them wrong and you either overstate assets or lose deductions you can’t get back.
Capitalize or Expense?
Every dollar spent on a fixed asset triggers the same question. Balance sheet or income statement? Routine maintenance that keeps an asset in its existing condition is a current expense. Replacing a worn belt, regreasing a bearing, swapping a filter: none of that creates new value, so none of it gets capitalized.
The IRS tangible property regulations set out three tests. Meet any one and the cost is a capital improvement:
- Betterment. The expenditure fixes a pre-existing defect, adds to the asset’s size or capacity, or materially increases its productivity, efficiency, or output.
- Restoration. The expenditure replaces a major component or substantial structural part, or returns a non-functional asset to working condition.
- Adaptation. The expenditure converts the asset to a new or different use outside its original purpose.
Upgrading a production line to a faster automation system is a betterment. Replacing an entire roof structure is a restoration. Converting warehouse space into a retail showroom is an adaptation. All three get capitalized.1Internal Revenue Service. Tangible Property Regulations – Frequently Asked Questions
The De Minimis Safe Harbor
Even a cost that meets one of the three tests can still be expensed under the IRS de minimis safe harbor election. Businesses with an applicable financial statement (audited, or filed with the SEC) can expense items up to $5,000 per invoice or per item. Without one, the threshold is $2,500.1Internal Revenue Service. Tangible Property Regulations – Frequently Asked Questions
This is where companies slip. The dollar threshold is an administrative shortcut, not a replacement for the betterment/restoration/adaptation analysis. An $1,800 item that would technically qualify as a betterment gets expensed if your policy sits at $2,500. But an item above your threshold still has to pass one of the three tests before you capitalize it.
What Belongs in the Cost Basis
Once you’ve decided to capitalize, the invoice price is only the starting point. The basis includes every cost necessary to get the asset ready for its intended use:
- Purchase price, net of discounts taken
- Inbound freight and delivery charges
- Installation labor and materials
- Testing and calibration before the asset goes into production
- Non-recoverable sales tax on the purchase
Installation and testing costs are the ones most often dropped into period expense by mistake. Every dollar left out of the basis is a dollar of depreciation you’ll never claim.
Recording the Addition and When Depreciation Starts
The entry itself is a one-liner. Debit the appropriate fixed asset account (Machinery and Equipment, Buildings, Vehicles) for the full capitalized cost and credit Cash or Accounts Payable. When you’re adding a component to an existing asset instead of buying a standalone piece of equipment, the debit still goes to the same asset account, increasing its carrying value.
Depreciation does not start on the purchase date or the delivery date. It starts on the placed-in-service date: the day the asset is installed, tested, and ready for use in your operations. Buy a machine in November but finish installing it in January, and January is when depreciation begins. That date drives both GAAP book depreciation and MACRS tax depreciation.
Book Depreciation Under GAAP
For financial reporting, pick the method that best reflects how the asset delivers value. Two do most of the work.
Straight-line spreads depreciable cost (original cost minus estimated salvage value) evenly across the useful life. A $100,000 machine with a $10,000 salvage value and a 10-year life generates $9,000 of depreciation each year. Good fit for assets that deliver roughly equal value every year, like office furniture or a building.
Double declining balance is accelerated. It applies twice the straight-line rate to the asset’s remaining book value each period, producing larger deductions in the early years and smaller ones later. That better matches assets that lose productivity or efficiency as they age. Total depreciation over the life of the asset is the same either way; only the timing changes.
The method you use for books has no bearing on tax depreciation. Federal tax follows its own rules.
Tax Depreciation Under MACRS
Most tangible business property is depreciated for federal tax under the Modified Accelerated Cost Recovery System. MACRS assigns each asset to a property class, and each class has a fixed recovery period:
- 5-year property: automobiles, trucks, computers, office machinery, research equipment
- 7-year property: office furniture, fixtures, and most machinery that doesn’t fit another class
- 15-year property: land improvements like fences, roads, sidewalks, and qualified improvement property
- 27.5-year property: residential rental buildings
- 39-year property: nonresidential (commercial) buildings
The class controls how quickly you can write the asset off, which flows straight into your tax bill.2Internal Revenue Service. Publication 946 – How To Depreciate Property
Conventions
MACRS also applies a convention that fixes how much depreciation you claim in the year of acquisition and the year of disposal. The default half-year convention treats every asset as if placed in service at the midpoint of the year, regardless of the actual date. Buy on January 5 or November 20 and either way you get half a year in year one.
The mid-quarter convention overrides that when more than 40% of the total depreciable basis of all MACRS property placed in service that year lands in the last three months. When it applies, each asset is treated as placed in service at the midpoint of its own quarter. That usually shrinks first-year deductions for Q4 acquisitions, so heavy late-year buying can backfire if you haven’t run the math.2Internal Revenue Service. Publication 946 – How To Depreciate Property Buildings use a mid-month convention instead and are excluded from the 40% test.3eCFR. 26 CFR 1.168(d)-1 – Half-Year and Mid-Quarter Conventions
Section 179 and Bonus Depreciation for 2026
Two elections let you accelerate tax depreciation far past the standard MACRS tables. Used together, they can wipe out the cost of an asset in the year it’s placed in service.
Section 179
Section 179 treats the cost of qualifying property as an immediate expense instead of capitalizing and depreciating it. For 2026, the maximum deduction is $2,560,000, inflation-adjusted from the statutory $2,500,000 base.4Office of the Law Revision Counsel. 26 U.S. Code 179 – Election to Expense Certain Depreciable Business Assets
The deduction phases out dollar-for-dollar once total Section 179 property placed in service during the year exceeds $4,090,000. Place $5,090,000 of qualifying property in service and the maximum drops by $1,000,000 to $1,560,000. At $6,650,000 the deduction is gone entirely.4Office of the Law Revision Counsel. 26 U.S. Code 179 – Election to Expense Certain Depreciable Business Assets
Qualifying property includes most tangible personal property used in the business (machinery, equipment, vehicles, computers) along with certain real property improvements such as HVAC systems, roofing, and security systems. The deduction also can’t exceed your business’s taxable income for the year, though unused amounts carry forward.
Bonus Depreciation
Bonus depreciation is an additional first-year deduction on qualifying new or used property. Under the Tax Cuts and Jobs Act of 2017 the allowance was 100%, then scheduled to phase down 20 percentage points a year starting in 2023, which would have put 2026 at just 20%.5Internal Revenue Service. Additional First Year Depreciation Deduction (Bonus) – FAQ
Legislation passed in 2025 permanently restored 100% bonus depreciation for property acquired on or after January 20, 2025. Assets placed in service in 2026 qualify for a full first-year write-off. Unlike Section 179, bonus depreciation has no dollar cap and no taxable income limitation, which makes it valuable for large acquisitions.
Ordering and Filing
Apply the two in order: Section 179 first, then bonus depreciation, then regular MACRS on whatever basis remains. Both are reported on IRS Form 4562, filed with the annual return.6Internal Revenue Service. Form 4562 – Depreciation and Amortization
One planning note. The Section 179 amount you elect reduces an asset’s depreciable basis before the mid-quarter test runs. A large election earlier in the year can shift the percentage of remaining basis placed in service in Q4, which can trigger or avoid the mid-quarter convention on your other assets.
Documentation and the Fixed Asset Register
For each capitalized addition, the IRS expects records showing when and how you acquired the asset, the purchase price, any improvement costs, Section 179 amounts taken, depreciation deducted, and how the asset was used. Purchase invoices, sales receipts, and real estate closing statements are the primary supporting documents.7Internal Revenue Service. What Kind of Records Should I Keep
Your internal fixed asset register does the day-to-day work. It functions as a subsidiary ledger that ties back to the fixed asset control accounts in your general ledger. For each asset, track a unique identification number, acquisition date, capitalized cost, depreciation method and schedule, physical location, and responsible department. Without that register, reconciling the balance sheet to physical reality is guesswork.
Walk the facility periodically. Confirm that recorded assets still exist and are still where the register says they are. Physical counts surface assets that have been scrapped, moved, or left idle without being written off, and ghost assets left on the books inflate total assets and understate losses.
Disposal
Accounting for a fixed asset doesn’t end when you stop using it. When you sell, scrap, or retire an asset, you remove both the original cost and all accumulated depreciation from the books, record any proceeds, and recognize the resulting gain or loss.
The math is simple. Sale price above net book value (original cost minus accumulated depreciation) is a gain. Sale price below book value is a loss. Fully depreciated and disposed of for nothing? Zero out the cost and accumulated depreciation with no gain or loss.
Say you capitalized a machine at $50,000 and have taken $35,000 in accumulated depreciation, leaving a $15,000 book value. Sell it for $20,000 and the entry debits Cash $20,000, debits Accumulated Depreciation $35,000, credits Machinery $50,000, and credits Gain on Disposal $5,000. Sell it for $8,000 and you debit a $7,000 loss instead of crediting a gain.
Record disposals as they happen. An asset sitting in a scrap pile for six months while still carried at $15,000 overstates assets and understates losses for every month it lingers.