Section 168 and Section 179 are two different routes to deducting the cost of business property, and for 2026 the choice usually comes down to this: Section 168(k) bonus depreciation gives you an automatic 100 percent write-off in year one with no dollar cap, while Section 179 lets you elect immediate expensing up to $2,560,000 but cannot push your business into a loss. When comparing Section 168 vs. 179 depreciation, bonus is the heavier hammer and Section 179 is the more precise tool. Most 2026 buyers will lean on bonus depreciation by default and use Section 179 to cover property bonus won’t reach or to manage how much deduction they actually take.
What Each Section Covers
Section 168 is the broader statute. It contains both the Modified Accelerated Cost Recovery System (MACRS), which is the default method for depreciating business property over a set recovery period, and the bonus depreciation rules in subsection (k) that let you deduct a large percentage of qualifying property in the first year.1Office of the Law Revision Counsel. 26 U.S. Code 168 – Accelerated Cost Recovery System If you do nothing special, MACRS applies automatically and spreads the cost across 3, 5, 7, 15, 27.5, or 39 years depending on the asset.
Section 179 is an election. You claim it on Form 4562, you pick which assets to apply it to, and you decide how much of each asset’s cost to expense. It converts what would otherwise be multi-year MACRS depreciation into a single-year deduction, subject to dollar caps and an income limit that bonus depreciation does not have.
Bonus Depreciation Under Section 168(k) in 2026
The One, Big, Beautiful Bill restored a permanent 100 percent bonus depreciation deduction for qualified property acquired after January 19, 2025.2Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One, Big, Beautiful Bill This replaced the phase-down that had taken bonus to 40 percent for 2025 and 20 percent for 2026 under the original Tax Cuts and Jobs Act schedule. Property acquired before January 20, 2025, remains on the old schedule, so the acquisition date, not just the placed-in-service date, controls which rules apply.
Bonus depreciation covers tangible personal property with a MACRS recovery period of 20 years or less. Both new and used property qualifies, provided you had no prior ownership interest in the asset, did not acquire it from a related party, and did not previously use it before purchasing.3eCFR. 26 CFR 1.168(k)-1 – Additional First Year Depreciation Deduction It does not cover nonresidential real property, residential rental property, assets required to use the Alternative Depreciation System, or property acquired from related parties.
Two features set bonus apart from Section 179. First, there is no dollar ceiling, so a $10 million equipment purchase can be fully deducted in year one. Second, bonus depreciation can generate or increase a net operating loss, with no income-based cap to stop it. The flip side is that it’s largely all-or-nothing: you either take bonus on every qualifying asset in a given class or you elect out for the entire class. For the first tax year ending after January 19, 2025, there is a one-time transition election to take 40 percent (or 60 percent for long-production-period property and certain aircraft) instead of 100 percent, aimed at taxpayers who prefer to spread deductions across years.2Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One, Big, Beautiful Bill
Section 179 Expensing in 2026
For tax years beginning in 2026, the maximum Section 179 deduction is $2,560,000. That limit begins shrinking dollar-for-dollar once total Section 179 property placed in service during the year exceeds $4,090,000, and phases out entirely at $6,650,000 in qualifying purchases.4Internal Revenue Service. Publication 946 – How To Depreciate Property Both thresholds are indexed for inflation.
Section 179 covers tangible personal property used in the active conduct of a trade or business, including machinery, equipment, and off-the-shelf software. It also reaches qualified real property that bonus depreciation often does not: interior improvements to nonresidential buildings, roofs, HVAC systems, fire protection and alarm systems, and security systems.5Office of the Law Revision Counsel. 26 U.S. Code 179 – Election to Expense Certain Depreciable Business Assets The property must be purchased, not gifted or inherited, and used in a business you actively run.
The Taxable Income Cap and Carryforward
Section 179 cannot exceed total taxable income from all of your active trades or businesses. It cannot create or increase a net operating loss. A business with $800,000 of income that elects to expense $1,000,000 gets a $800,000 deduction for the current year, and the disallowed $200,000 carries forward indefinitely to any future year with enough income.5Office of the Law Revision Counsel. 26 U.S. Code 179 – Election to Expense Certain Depreciable Business Assets That carryforward makes 179 a low-risk election even in a lean year, because nothing is permanently lost.
A Section 179 election can be made, changed, or revoked by filing an amended return within the time the IRS allows for the applicable tax year. You don’t need IRS consent to revoke, but the revocation itself is irrevocable for that year.6Internal Revenue Service. Instructions for Form 4562
The Order the Deductions Apply
When an asset qualifies for more than one method, the three deductions stack in a mandatory sequence. Section 179 goes first, then bonus depreciation, then regular MACRS on whatever basis is left.6Internal Revenue Service. Instructions for Form 4562 Each step reduces the basis available to the next one.
With bonus at 100 percent, the ordering is often invisible: if you take full bonus on the whole cost, there’s nothing left for MACRS and no reason to also elect 179. The sequence matters in specific situations. You elected out of bonus for a class of property and want to apply 179 selectively to individual assets inside that class. The asset qualifies for 179 but not for bonus. You want to use 179’s income limit as a brake, keeping some deduction in year one and letting the rest ride on MACRS. In each of these the order decides what the numbers look like.
When Section 179 Still Beats Bonus Depreciation
With permanent 100 percent bonus, it’s easy to assume Section 179 is obsolete. It isn’t. Four situations favor it.
Qualified real property. Interior improvements, roofs, HVAC, fire protection, alarm, and security systems in nonresidential buildings fall squarely inside Section 179. Bonus can reach some of these as 15-year property, but 179 provides a reliable alternative when the acquisition-date or related-party rules get in the way.
Picking which assets and how much. Bonus is all-or-nothing within a class. Section 179 is asset-by-asset and dollar-by-dollar. A business with $500,000 in taxable income can elect exactly $500,000 of Section 179 across its chosen assets and leave the rest on MACRS, keeping the return at zero without crossing into loss territory.
Avoiding a net operating loss. Bonus depreciation has no income guardrail; it will happily create or deepen an NOL. For a profitable business that wants to zero out tax without triggering NOL carryforward limitations, 179’s income cap is the cleaner result.
After electing out of bonus. If you’ve elected out of bonus for a class of property to preserve deductions for higher-income years ahead, Section 179 can still be applied inside that class on individual assets. The two elections operate independently.
Vehicle Depreciation Caps Change the Math
Vehicles are where business owners most often overestimate what they can actually deduct. Passenger automobiles sit under Section 280F’s annual caps regardless of which depreciation method you use.
For passenger vehicles placed in service in 2026, the ceilings are:7Internal Revenue Service. Revenue Procedure 2026-15
- First tax year: $20,300 with bonus depreciation, $12,300 without
- Second tax year: $19,800
- Third tax year: $11,900
- Each succeeding year: $7,160
A $60,000 sedan used entirely for business takes roughly six years to recover even with bonus, because the first-year deduction is capped at $20,300 rather than the full price. The caps bite regardless of whether you elected 179 or claimed bonus.
Vehicles with a gross vehicle weight rating over 6,000 pounds escape the passenger auto caps, which is why heavy SUVs, pickups, and vans are such common business purchases. SUVs between 6,000 and 14,000 pounds face a separate Section 179 ceiling of roughly $32,000 for 2026 rather than the full $2,560,000, but bonus depreciation on these heavy vehicles is not capped by 280F. A $75,000 truck over 6,000 pounds GVWR used 100 percent for business can be fully deducted in year one through bonus depreciation alone.
All vehicles and other listed property must be used more than 50 percent for business to qualify for either Section 179 or bonus. Business use of 70 percent gets you 70 percent of the otherwise allowable deduction. If business use drops to 50 percent or below in a later year, you have to recapture the excess depreciation already claimed and switch to straight-line going forward.8eCFR. 26 CFR 1.280F-6 – Special Rules and Definitions
Your State May Not Follow Federal Rules
Federal and state depreciation rules often diverge. Roughly 15 states fully conform to federal bonus depreciation; several allow only a fraction or decouple entirely. About a dozen states maintain their own Section 179 caps, ranging from $25,000 to $500,000, well below the federal $2,560,000.
The OBBB’s permanent 100 percent bonus will not flow through to every state return. States that conform to the Internal Revenue Code as of a fixed date won’t pick up the change until their legislature updates that date, and some states decouple from bonus depreciation entirely regardless of the federal percentage. Confirm your state’s conformity before you assume the full federal deduction will reduce your state taxable income by the same amount.