Section 179 vs Bonus Depreciation: Which One to Use

Your accountant says “just write it off this year” and you nod along. Then you see two different numbers on two different schedules of your return. One is labeled Section 179 and one is labeled bonus depreciation. You have no idea why there are two.

Here is the short version. They do almost the same thing: a full deduction in year one. But the IRS built them with different knobs. One has a cap and lets you choose asset by asset. The other has no cap but applies to an entire category of property at once. Knowing which one is doing the work on your return matters when you are planning next year’s purchase, not just filing this year’s.

Scope of this guide: businesses of any entity type (sole prop, LLC, S-corp, C-corp, partnership) buying tangible business property in 2026. This is not about real estate structures, vehicle mileage logs, or rental cost segregation studies. Those get their own guides, linked below.

#What each one actually does

Both provisions let you deduct 100% of an asset’s cost in the year you place it in service, instead of depreciating it over 5, 7, or 15 years. The mechanics are not the same.

Section 179 is an election. You choose which specific assets to expense and how much of each one, up to the annual dollar cap. You can section 179 one machine and depreciate the one next to it normally if you want to. The deduction is also limited to your business’s taxable income before the deduction. This means Section 179 cannot create or increase a loss.

Bonus depreciation is automatic unless you elect out of it. It applies to an entire class of property at once (all 5-year property, for example). There is no business-income limit. So bonus depreciation can push a profitable year into a loss on paper. That loss may be usable against other income depending on your entity type and the excess business loss rules.

#The 2026 dollar limits

For tax year 2026, Section 179 lets a business expense qualifying property placed in service during the year. The cap is $2,560,000. That cap reduces dollar-for-dollar once total qualifying purchases for the year exceed $4,090,000. The deduction disappears entirely once purchases clear the cap-plus-phase-out ceiling.

For scope: these are the 2026 figures under the One Big Beautiful Bill Act (OBBBA), signed July 4, 2025. OBBBA roughly doubled both numbers from the pre-OBBBA 2025 limits. Those were $1,250,000 (cap) and $3,130,000 (phase-out start). It then set $2,500,000 and $4,000,000 for 2025 itself. Both figures are now indexed for inflation starting in 2026. Prior-year figures are historical and will not match the 2026 module above.

Bonus depreciation has no overall dollar cap. Passenger cars still have their own yearly limits. It is a rate (100% for 2026) applied to the cost of qualifying property. It is limited only by what qualifies, not by how much you spend.

#When Section 179 does the better job

If you want to preserve future depreciation, check the bonus election too. Section 179 lets you pick specific assets, but eligible property left unexpensed generally gets bonus depreciation by default. Electing out of bonus applies to the entire property class, not just your chosen machine.

You are near the line on business income. Section 179 cannot exceed your business’s taxable income before the deduction. That makes it the safer tool when you are not sure whether a full write-off would create a loss you cannot use this year.

Say you bought a heavy SUV. Section 179 may be capped at $32,000 in 2026 for an SUV meeting the statutory weight and vehicle definitions. Eligible remaining basis may qualify for bonus depreciation, but business-use and other passenger-auto rules still apply. A heavier vehicle is not automatically deductible in full.

#When bonus depreciation does the work 179 can’t

You bought more than the 179 cap or phase-out allows. Once a single year’s purchases exceed the $4,090,000 phase-out threshold, Section 179 shrinks fast. Bonus depreciation keeps covering the rest at 100%, no cap, no phase-out.

You want the deduction even in a loss year. Say you have a new business, or a business with a rough year that still wants full expensing on new equipment. You can use bonus depreciation to create or deepen a loss. This is subject to the excess business loss, basis, at-risk, and passive loss rules.

You did not make an election. Section 179 is an affirmative choice on the return. Bonus depreciation applies automatically for eligible property unless you file an election out of it. That is why it is easy to end up using more bonus depreciation than you realized.

#The order businesses actually use

For most equipment-heavy small businesses buying under the Section 179 cap in a single year, the order on the return is:

1. Apply Section 179 first, up to the cap, to the specific assets you choose.
2. Apply 100% bonus depreciation to whatever basis is left on qualifying property, including any amount above the 179 cap or on assets you did not elect 179 for.
3. Regular MACRS depreciation only applies to anything left over, which for most small purchases is nothing.

#A worked example that reconciles

A landscaping company buys $180,000 of equipment in 2026. That is a $60,000 mower fleet and a $120,000 skid steer with attachments. Taxable business income before the deduction is $150,000.

Step 1, Section 179 election. The owner elects Section 179 on the $60,000 mower fleet. Section 179 deduction: $60,000. This choice does not preserve future depreciation on the skid steer if 100% bonus applies to it.

Step 2, bonus depreciation on the rest. Assume the $120,000 skid steer meets the separate bonus eligibility and acquisition-date tests. The owner does not elect out for its class. Bonus deduction: $120,000.

Step 3, add it up.

• Section 179: $60,000
• Bonus depreciation: $120,000
• Total year-one deduction: $60,000 + $120,000 = $180,000

That equals the full $180,000 purchase price. Nothing was double-counted or left on the MACRS schedule. Because the $60,000 Section 179 amount is well under the $150,000 taxable-income limit, the full election is usable this year.

If the owner instead elected Section 179 on the full $180,000: with only $150,000 of taxable business income before the election in this example, the current-year Section 179 deduction is limited to $150,000. The remaining $30,000 cannot simply be called a current-year Section 179 deduction. Its carryforward and interaction with bonus need to be figured under the applicable basis and election rules. The $60,000 Section 179 plus $120,000 bonus calculation above is the fully reconciled first-year example.

#What this does and doesn’t change about state taxes

This is federal law. Texas has no state income tax, so Texas-based pass-through owners get the federal benefit with no state-level wrinkle. If you operate in other states, this is a scope note, not a universal rule. Several states “decouple” from federal bonus depreciation and Section 179 limits. That means your state return may require an addback this year and a subtraction in later years. Confirm your specific state’s conformity before assuming the federal number carries through, especially if you have multi-state nexus.

#Common questions

#Do I have to choose one or the other?

Section 179 on selected assets and bonus on eligible remaining basis can be used in the same year. An election out of bonus applies by property class. Whether using both is useful depends on the taxpayer’s income and the assets.

#Can I use Section 179 if my business lost money this year?

The business taxable-income limit can include qualifying active income outside that one activity for an individual owner. A corporation with no business taxable income generally cannot use a current-year Section 179 deduction. But a sole proprietor can be different. A loss in one activity may still leave other active trade or business income that affects the limit. An unused election may carry forward. Bonus depreciation is not subject to Section 179’s income limit.

#What property actually qualifies for bonus depreciation?

Generally, bonus can apply to MACRS property with a recovery period of 20 years or less. This includes many equipment items and cost-segregation components (from a cost segregation study). Other eligibility rules still apply. Land and the building structure itself (27.5 or 39-year property) do not qualify for bonus depreciation.

#Does buying a used machine still qualify?

Generally yes for both provisions. You need to not have previously used the asset, not have bought it from a related party, and your basis in it must not be figured by reference to the seller’s basis. Most ordinary arm’s-length used-equipment purchases qualify.

#What happens if I go over the Section 179 phase-out threshold?

Above $4,090,000 of total qualifying purchases in the year, the $2,560,000 cap reduces dollar-for-dollar. Bonus depreciation keeps applying at 100% regardless, so very large purchase years lean almost entirely on bonus depreciation rather than 179.

#Is bonus depreciation really permanent now?

Our reading, confirm before relying on it: OBBBA removed the scheduled phase-down (which was headed to 0% by 2027). It set the rate at 100% with no sunset date written into the statute for property acquired after January 19, 2025. “Permanent” in tax law means “until Congress changes it again,” not “guaranteed forever.”

#Do I need an appraisal or study to use either one?

For ordinary equipment, the invoice and placed-in-service date are usually enough. For vehicles, also keep a mileage log: if business use is 50% or less, neither Section 179 nor bonus applies. A cost segregation study is a separate, specialized process used specifically for real estate, not for equipment purchases covered by this guide.

#Ready to talk through your situation?

The right split between Section 179 and bonus depreciation depends on your business’s income this year, next year’s expected income, and which specific assets you want to control. Book a free 20-minute Tax Discovery call, Google Meet, no pitch, free advice either way.