What Is a Section 179 Deduction and How Does It Work?

The Section 179 deduction lets a business write off the full cost of qualifying equipment, software, and certain building improvements in the year the property is placed in service, rather than depreciating those costs over many years. For the 2026 tax year, a business can expense up to $2,560,000 of qualifying property, with the deduction phasing out dollar for dollar once total qualifying purchases pass $4,090,000. The One Big Beautiful Bill Act, signed in July 2025, roughly doubled the prior caps and indexed the new base amounts to inflation.

The 2026 Dollar Limits

Two caps work together. The deduction limit is $2,560,000 of qualifying property placed in service during the year. The investment ceiling is $4,090,000: every dollar of qualifying purchases above that reduces the available deduction by a dollar. Buy $4,290,000 of qualifying equipment, and the $200,000 overage cuts your maximum deduction to $2,360,000. Once total purchases hit $6,650,000, the deduction is gone entirely.¹

A third ceiling sits on top of those. Your Section 179 deduction cannot exceed the taxable income from the active conduct of your trade or business for the year. It cannot be used to create or increase a net operating loss. Anything disallowed by the income limit carries forward to future years with no expiration.²

Estates and trusts cannot make the election at all.³

What Property Qualifies

Section 179 covers most tangible personal property used in the active conduct of a business: equipment, machinery, computers, office furniture, tools. Off-the-shelf software qualifies too, meaning commercially available programs bought with a standard license rather than custom-developed code.⁴

Certain improvements to non-residential buildings also qualify. These include interior renovations (qualified improvement property), new roofing, HVAC systems, fire suppression and alarm systems, and security systems. The improvement must be to a commercial building you already use in your business, and it cannot enlarge the building’s footprint or alter its internal structural framework.⁵

Used equipment counts. It just has to be new to your business and acquired through a genuine purchase.

What Does Not Qualify

Several categories are excluded, and some catch owners off guard:

Land and land improvements. Parking areas, fences, swimming pools, docks, and bridges are all excluded even when they serve a clear business purpose.
Property used mostly outside the United States.
Property used by governmental units, tax-exempt organizations, or foreign persons. Limited exceptions apply where a tax-exempt organization uses the property to generate unrelated business taxable income.
Property leased to others by a noncorporate lessor. Corporations are exempt from this restriction.
Property received as a gift or inheritance. It was not acquired by purchase.

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Business Use, Ownership, and Timing Rules

The property must be used for business more than 50% of the time, measured by actual usage hours or days. Mixed-use property gets a proportional deduction: buy a $2,000 laptop and use it 80% for business, and Section 179 applies to $1,600. Drop below 50% business use, and it does not qualify at all.⁶

The asset must be acquired by purchase, not by gift, inheritance, or a transaction where your basis carries over from the prior owner. Purchases from related parties are disqualified, though the “family” definition for this rule is narrower than most people expect. It covers only your spouse, ancestors, and lineal descendants. Siblings are not included, so buying equipment from a brother or sister can still qualify.⁴

The property must also be placed in service before the end of the tax year. Placed in service means installed, tested, and ready for its intended business function. Ordering equipment in December but not receiving it until January pushes the deduction to the following year.

Business Vehicles

Vehicles are one of the most common Section 179 claims, and the rules vary sharply by weight class.

Passenger Vehicles Under 6,001 Pounds

Cars, small crossovers, and light trucks fall under the luxury automobile depreciation caps. For 2026, the maximum first-year deduction (combining Section 179, bonus depreciation, and regular MACRS) is $20,300 if bonus depreciation applies, or $12,300 if it does not. These caps override the general Section 179 limit. You cannot expense more than $20,300 on a sedan no matter what the sticker says.⁷

Heavy SUVs Between 6,001 and 14,000 Pounds

Vehicles with a gross vehicle weight rating above 6,000 pounds but no more than 14,000 pounds get a larger, still-capped deduction. For 2026, up to $32,000 of the cost can be expensed under Section 179, with the remainder recovered through bonus depreciation and regular MACRS. Many full-size SUVs and larger pickup trucks fall here, which is the origin of the “6,000-pound rule” in year-end planning conversations.

Heavy Vehicles Over 14,000 Pounds

Trucks, vans, and specialty vehicles exceeding 14,000 pounds GVWR are not subject to the SUV cap or the luxury auto limits. A qualifying heavy-duty work truck can be fully expensed up to the general $2,560,000 deduction limit.

All vehicle deductions still require more than 50% business use. The IRS pays close attention to vehicle claims, so a contemporaneous mileage log separating business and personal driving is worth keeping.

Section 179 vs. Bonus Depreciation

Section 179 and bonus depreciation under Section 168(k) both accelerate write-offs, but they work differently and often work together. The One Big Beautiful Bill Act reinstated 100% bonus depreciation for qualifying property placed in service after January 19, 2025, reversing a phase-down that had dropped the rate to 40% earlier that year.⁸

The main differences:

Section 179 cannot exceed business taxable income. Bonus depreciation has no income limit and can create or increase a net operating loss.
Section 179 phases out once purchases exceed $4,090,000. Bonus depreciation has no spending ceiling, so larger businesses often rely on it instead.
Section 179 covers a slightly broader range of property, including off-the-shelf software and certain building improvements. Bonus depreciation applies primarily to property with a recovery period of 20 years or less.
Section 179 is applied first, reducing the asset’s basis. Bonus depreciation then applies to whatever basis remains. Standard MACRS covers anything left after both.

For most small businesses buying well under the phase-out threshold, the practical result is the same: a full first-year write-off. The distinction matters when you are near the income limit, or when you want asset-by-asset control. Section 179 is elective per asset, while bonus depreciation generally applies to all eligible property in a class unless you opt out.

How to Claim It

The deduction is claimed on IRS Form 4562, Depreciation and Amortization, attached to the business tax return. Part I is dedicated to Section 179 and asks for a description of each asset, its cost (business-use portion only), and the amount you elect to expense.⁹

For each asset, you will need:

Date of acquisition, documented by a bill of sale, invoice, or financing agreement.
Date placed in service, meaning when the asset was installed and ready for business use, not necessarily when it was ordered or delivered.
Total cost, including freight, delivery, and installation charges.
Business-use percentage. Only the business portion of a mixed-use asset is eligible.

The election is made on the return filed for the year the property was placed in service. If you acquired the asset through a trade-in, you include only the additional cash paid, not the carryover basis from the old asset.⁶ Keep receipts, invoices, and usage logs for at least three years after filing.¹⁰

When Recapture Applies

If business use of the property drops to 50% or below in any year after you claim the deduction, the IRS takes back part of the benefit. Vehicles that gradually shift toward personal use are the usual trigger.

The recapture calculation: take the Section 179 amount originally deducted, then subtract the depreciation you would have been allowed under standard MACRS rules for the years you held the property. The difference is added back to your income as ordinary income in the year business use drops below the threshold. You report it on Form 4797, Part IV.¹¹

You lose the timing advantage of the immediate write-off, not the entire deduction, since you still get credit for the depreciation you would have taken anyway. Reliable year-by-year records of business use are the only defense against a recapture challenge on audit.⁴

1
Internal Revenue Service. Publication 463 (2025), Travel, Gift, and Car Expenses
2
eCFR. 26 CFR 1.179-3 – Carryover of Disallowed Deduction
3
eCFR. 26 CFR 1.179-1 – Election to Expense Certain Depreciable Assets
4
Office of the Law Revision Counsel. 26 USC 179 – Election to Expense Certain Depreciable Business Assets
5
Internal Revenue Service. Publication 946 (2024), How to Depreciate Property
6
Internal Revenue Service. 2025 Instructions for Form 4562 Depreciation and Amortization
7
Internal Revenue Service. Rev. Proc. 2026-15 – Depreciation Limitations for Passenger Automobiles
8
Internal Revenue Service. One Big Beautiful Bill Provisions
9
Internal Revenue Service. About Form 4562, Depreciation and Amortization
10
Internal Revenue Service. How Long Should I Keep Records?
11
Internal Revenue Service. Instructions for Form 4797 – Sales of Business Property