Section 179 vs Bonus Depreciation in 2026: Which Deduction Should You Use?
With bonus depreciation back at 100% permanently, Section 179 is no longer the obvious first choice. The two provisions solve different problems.
Section 179 and bonus depreciation are both first-year expensing provisions that allow immediate deduction of asset costs, but they differ in four decisive ways: Section 179 is capped in dollar amount and phases out with total purchases, cannot create or increase a net loss, is elected asset by asset, and is more widely conformed by states; bonus depreciation under Section 168(k) is uncapped, can create a loss, is elected by class life for all assets in that class, and is decoupled by many states. In 2026 both provide a 100% deduction, so the choice turns on these mechanics rather than on the deduction rate.
The 2026 Section 179 Limits
The OBBBA substantially increased Section 179. For tax years beginning after December 31, 2024, the expensing cap rose to $2.5 million with a phase-out threshold of $4 million, both indexed for inflation. For 2026 the indexed figures are approximately $2.56 million and $4.09 million, and you should confirm the exact published amounts before filing.
The phase-out works dollar for dollar. If total qualifying property placed in service during the year exceeds the threshold, the maximum Section 179 deduction is reduced by the excess, reaching zero once purchases exceed the threshold by the amount of the cap.
Section 179 is also limited to taxable income from the active conduct of a trade or business. It cannot create a loss and it cannot increase one. Any disallowed amount carries forward indefinitely, but it sits there until you have income to absorb it.
The Four Differences That Actually Decide It
1. Loss creation. Bonus depreciation can drive taxable income negative and create a net operating loss. Section 179 cannot. If your goal is to generate a loss that offsets other income, Section 179 is structurally incapable of doing it and bonus depreciation is the only tool.
2. Election granularity. Section 179 is elected asset by asset, and you can even elect a partial amount on a single asset. Bonus depreciation is all-or-nothing by class life for the year. If you want to expense one piece of equipment and depreciate another of the same class life normally, only Section 179 gives you that control.
3. State conformity. This is the most underrated factor. Many states decouple from federal bonus depreciation entirely, requiring an addback and a separate state depreciation schedule, while conforming to Section 179 at some level. In a decoupling state, using Section 179 can produce a state deduction that bonus depreciation would not, and the state tax difference can exceed the federal timing difference.
4. Property eligibility. Section 179 covers some things bonus does not, notably certain improvements to nonresidential real property placed in service after the building was first placed in service: roofs, HVAC, fire protection and alarm systems, and security systems. These are 39-year property, so they are not bonus-eligible, but they can be expensed under Section 179. For a commercial owner replacing a roof, that distinction is the entire deduction.
Recapture Rules Differ Too
If business use of Section 179 property drops to 50% or less before the end of its recovery period, you must recapture the excess deduction as ordinary income in that year, computed as the Section 179 amount taken minus the depreciation that would have been allowed. Bonus depreciation has no equivalent business-use recapture rule, though listed property rules can still apply.
On disposition, both are recaptured as ordinary income under Section 1245 to the extent of gain. There is no difference at sale, only during the holding period.
This makes Section 179 riskier for assets whose business use might decline, particularly vehicles and equipment that could shift to personal or mixed use.
Vehicles: Where Both Provisions Get Complicated
Passenger automobiles are subject to the luxury auto limitations of Section 280F, which cap total first-year depreciation including bonus at an inflation-adjusted amount that is far below the vehicle's cost. Section 179 does not escape these caps for passenger autos.
The well-known exception is a vehicle with a gross vehicle weight rating above 6,000 pounds, which falls outside the passenger automobile definition. SUVs above that weight are subject to a separate Section 179 cap, indexed annually, while bonus depreciation on them is not similarly capped. Vehicles above 6,000 pounds GVWR that are not SUVs, such as certain pickups with a bed of at least six feet, avoid the SUV cap as well.
In all cases, business use must exceed 50% for accelerated methods, and mileage logs are the evidence. This is one of the most frequently examined items on a small business return, and reconstructed logs do not hold up.
The Ordering Rule and How We Usually Apply It
The statutory ordering is fixed: Section 179 first, then bonus depreciation on remaining basis, then regular MACRS. You cannot reverse it.
Our general approach is to reserve Section 179 for the things bonus cannot reach, principally qualifying nonresidential building improvements such as roofs and HVAC, and to use it in states that decouple from bonus. Then we apply bonus depreciation to everything else, since it is uncapped and can create the loss that drives the plan.
There is one more consideration that cuts against maximizing either: the Section 199A qualified business income deduction. Large first-year deductions reduce QBI, and for taxpayers inside the phase-in range the marginal effect can be counterintuitive. We model the QBI outcome before finalizing the depreciation elections, not after.
Choosing Between Them: A Short Decision Path
Do you need the deduction to create a loss that offsets other income? Use bonus depreciation. Section 179 cannot do it.
Are you deducting a roof, HVAC unit, fire protection, or security system on a nonresidential building? Use Section 179. Bonus depreciation cannot reach 39-year property.
Does your state decouple from bonus depreciation? Lean toward Section 179 to the extent the state conforms, and compute the combined federal and state result rather than the federal result alone.
Do you want asset-level control, expensing some items and depreciating others in the same class? Use Section 179, because the bonus election is made by class.
Is total spending near the phase-out threshold? Section 179 begins disappearing, and bonus depreciation becomes the only meaningful option.
Key Takeaways
- Both give 100% in 2026, so the decision turns on loss creation, election granularity, state conformity, and property type.
- Only Section 179 can expense roofs, HVAC, fire protection, and security systems on nonresidential buildings.
- Only bonus depreciation can create a loss, which is what most real estate plans actually need.
- State decoupling from bonus depreciation frequently makes Section 179 the better combined-tax answer.
- Section 179 first, then bonus, then MACRS is a statutory ordering you cannot rearrange.
Frequently Asked Questions
What is the Section 179 limit for 2026?
The OBBBA raised the cap to $2.5 million with a $4 million phase-out threshold for tax years beginning after December 31, 2024, both indexed for inflation. For 2026 the indexed amounts are approximately $2.56 million and $4.09 million. Confirm the published figures before filing, since they adjust annually.
Can Section 179 create a net operating loss?
No. Section 179 is limited to taxable income from the active conduct of a trade or business and cannot create or increase a loss. Any disallowed amount carries forward indefinitely. If you need a deduction that produces a loss, bonus depreciation is the only option of the two.
Which is better for a new roof on a commercial building?
Section 179. A roof on nonresidential real property is 39-year property and therefore not eligible for bonus depreciation, but it is specifically included in the Section 179 definition of qualified real property along with HVAC, fire protection and alarm systems, and security systems.
Do states treat Section 179 and bonus depreciation the same?
Often not. Many states decouple from federal bonus depreciation and require an addback with a separate state depreciation schedule, while conforming to Section 179 at some level, sometimes with a lower cap. In those states the choice between the two provisions can change your state tax materially.
What happens if business use of Section 179 property drops below 50%?
You must recapture the excess benefit as ordinary income in the year business use falls to 50% or less, measured as the Section 179 deduction taken minus the depreciation that would otherwise have been allowed. Bonus depreciation has no comparable business-use recapture rule during the holding period.
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