Section 179 Deduction: How to Write Off Equipment

An owner considering a truck, a piece of equipment, or computers before year-end may ask whether buying now creates a deduction. The equipment itself must make business sense, and it is just one piece of a broader year-end tax planning checklist. The tax reasoning behind the timing is where mistakes happen.

Section 179 is not complicated in theory. You buy equipment, you use it in your business, you deduct the cost this year instead of over several years. In practice, three things decide whether it actually works the way you expect: whether the equipment qualifies, whether you have enough business income to use the deduction, and whether it is physically ready to use before the calendar turns.

This is general information, not personalized advice. It is a plain-English map of how the deduction works for tax year 2026, so you can have a sharper conversation with whoever prepares your return.

#What Section 179 actually does

Normally, when a business buys equipment, the tax code makes you spread the deduction out. A $100,000 piece of machinery with a seven-year class life gets depreciated a little each year for seven years. Section 179 is an election that lets you skip that schedule and deduct the full cost in the year you start using the equipment.

It is named for IRC §179, and it applies to tangible personal property used in a trade or business: machinery, equipment, computers, office furniture, certain software, and some vehicles. It generally does not apply to real property like buildings (there are narrow exceptions for things like roofs and HVAC on nonresidential buildings, which is a separate conversation).

#Why it exists

Congress wants businesses investing in equipment now, not five years from now. A full first-year deduction is a bigger incentive than a deduction stretched thin over several years, especially for a small business weighing whether this is the year to buy the truck or the machine.

#New or used, both qualify

Unlike some depreciation rules, Section 179 does not require the equipment to be brand new. Used equipment qualifies, as long as it is new to your business and you did not buy it from a related party.

#The 2026 dollar limit and the phase-out

For tax years beginning in 2026, the maximum Section 179 election is $2,560,000 (IRC §179(b)(1), as indexed by Rev. Proc. 2025-32 §4.24). That is the most a business can elect to expense under Section 179 for the year, across all qualifying property.

#The phase-out, dollar for dollar

The limit is not available to every business at every spending level. Once your total qualifying purchases for the year exceed $4,090,000, the maximum deduction drops by one dollar for every dollar over that threshold.

Here is a worked example that reconciles end to end:

• A business places $5,000,000 of qualifying equipment in service in 2026.
• That is $910,000 over the $4,090,000 phase-out threshold (5,000,000 minus 4,090,000).
• The $2,560,000 maximum is reduced dollar-for-dollar by that excess: $2,560,000 minus $910,000 equals $1,650,000 of Section 179 still available.
• The remaining $3,350,000 of the purchase does not disappear. If the equipment meets the separate bonus-depreciation requirements, including the acquisition-date rule, the remaining eligible basis may qualify for 100% bonus depreciation in 2026.

For a small business well below the phase-out threshold, the placed-in-service deadline and the business-income limit may matter more than the dollar cap.

#The deadline that actually causes problems: placed in service

This is the rule that trips people up, far more often than the dollar limits.

“Placed in service” does not mean purchased, ordered, or paid for. It means the equipment is delivered, set up, and ready to be used in your business, by the end of your tax year. For a calendar-year business, that is December 31.

#What happens if you miss it

If equipment arrives or becomes usable in January instead of December, the deduction simply moves to next year’s return. It is not lost. But if you were counting on offsetting this year’s income, planning the purchase for “sometime in Q4” without confirming a realistic delivery and setup date is how that plan falls apart.

#Business-use percentage matters too

Section 179 requires the property be used more than 50% for business. If a piece of equipment or a vehicle is used partly for personal purposes, only the business-use percentage is eligible, and the deduction can be subject to recapture later if business use drops below 50% during the property’s class life.

#Section 179 vs. bonus depreciation: they are not competitors

A lot of confusion comes from treating these as alternatives. They are not. They are applied in sequence, generally in this order:

1. Section 179 is elected first, up to the dollar limit (after any phase-out).
2. 100% bonus depreciation generally applies to any remaining eligible cost if the property meets the separate Section 168(k) rules, including acquisition after January 19, 2025, and timely placement in service.

The practical difference that matters for planning:

• Section 179 cannot create or increase a business loss. It is capped by business taxable income (more below).
• Bonus depreciation has no such income limit and can create or deepen a loss.

So a business with a smaller profit this year sometimes gets more value by leaning on bonus depreciation rather than maxing out Section 179, and a business near the phase-out threshold has reasons to prefer one over the other. See our breakdown of how OBBBA restored 100% bonus depreciation for the acquisition-date rule in more detail. This is worth a specific conversation rather than a default “just take the biggest deduction,” which is exactly the kind of question a tax planning session is built for.

#The business-income limit

Even under the $2,560,000 dollar cap, Section 179 cannot exceed your business’s taxable income for the year (before the deduction itself, IRC §179(b)(3)). If the math would otherwise create a loss, the disallowed portion is not wasted. It carries forward and can be used in a future year when there is enough income to absorb it.

This is where the interaction with a spouse’s W-2 income or other business income on a joint return matters for a sole proprietor or single-member LLC, since taxable income for this limit is figured in a way that can include other active trade or business income. Scope note: this gets fact-specific fast by entity type and filing status. Treat the general rule above as the floor of the conversation, not the whole answer for your return.

#What actually qualifies (and what does not)

Generally qualifies:

• Machinery and equipment used in the business
• Office furniture and equipment
• Computers and off-the-shelf software
• Certain business vehicles (with special rules below)
• Some property used to furnish lodging, subject to the other Section 179 requirements
• Some improvements to nonresidential real property (roofs, HVAC, fire protection and alarm systems, security systems) under IRC §179(e)

Generally does not qualify:

• Land
• The building itself (the structural shell of nonresidential or residential real property)
• Property acquired from certain related parties

#The vehicle wrinkle

Vehicles get their own rules layered on top. Heavy SUVs with a gross vehicle weight rating over 6,000 lbs are capped at $32,000 of Section 179 for 2026 under §179(b)(5), even though the vehicle itself may cost more. Lighter passenger vehicles face separate “luxury auto” depreciation limits under §280F that are different from, and lower than, the heavy-SUV cap.

If vehicles are the main purchase driving this decision, check the vehicle’s gross vehicle weight rating, actual business-use percentage, and any separate passenger-auto limits rather than assuming the general equipment rule applies. S-corp owners buying a vehicle through the business have an extra layer of rules; see how vehicle write-offs work inside an S-corp.

#How to actually claim it

The mechanics are simpler than the rules around them:

• File Form 4562 (Depreciation and Amortization), Part I, with your timely filed return, including extensions.
• List each property: description, date placed in service, cost, and the elected Section 179 amount.
• Keep records: the invoice, the date it was ready for business use, and your business-use percentage if it is anything other than 100%.
• Coordinate with bonus depreciation on the same form if the purchase exceeds what Section 179 covers.

Good records at bookkeeping time are what make this defensible later. “We bought a truck in December” is not the same thing on an IRS notice as an invoice showing the delivery date and a mileage log showing business use. If the equipment purchase also changes your quarterly estimated payments, see quarterly estimates done right.

#Go deeper

• Section 179 vs bonus depreciation: which one to use, and when to use both
• Section 179 vehicles: which trucks and SUVs qualify, and the SUV cap

#Common questions

#Can I take Section 179 on equipment I financed instead of paid cash for?

Yes. Financing does not disqualify the deduction. You can take the full Section 179 deduction on financed equipment as long as it is placed in service by the deadline and otherwise qualifies, even if you are still making loan payments on it for years.

#Does Section 179 apply to software?

Yes, for off-the-shelf computer software that is readily available for purchase by the general public, not custom-developed software. Most standard business software qualifies.

#What if I order equipment in November but it doesn’t arrive until January?

It is placed in service in the year it arrives and becomes usable, which in that example is next year. The deduction follows the equipment, not the purchase date. Build in lead time if the deduction is timed to this year’s income.

#Is Section 179 the same as the §179D energy-efficient building deduction?

No. They share a number but are different provisions. §179 is the general equipment expensing election covered here. §179D is a separate energy-efficient commercial buildings deduction; under current law it is unavailable for property whose construction begins after June 30, 2026.

#Can a single-member LLC or sole proprietor use Section 179?

Yes. Section 179 is available to sole proprietorships, partnerships, S-corporations, and C-corporations, with the business-income limitation applied at the appropriate level for each entity type.

#Does the equipment have to be new?

No. Used equipment qualifies, as long as it is new to your business. Buying a used piece of machinery from an unrelated seller does not disqualify it.

#What happens if my business use of the equipment drops below 50% later?

Part of the deduction can be subject to recapture, meaning you add some of it back to income in the year business use drops below 50%, within the property’s class life. This is one more reason good usage records matter, not just at purchase but going forward.

#Can I use Section 179 and still have a loss for the year?

Not from the Section 179 deduction itself. Section 179 is limited to your business’s taxable income. Bonus depreciation, by contrast, can create or widen a loss, which is one reason the ordering between the two matters for a business near breakeven.

#Ready to talk through your situation?

The dollar limits in 2026 are generous enough that most small-business equipment purchases are not actually constrained by the cap. What usually decides the outcome is timing, business income, and whether the purchase is structured the way the rules expect. If you are weighing an equipment purchase before year-end, a 20-minute Tax Discovery call is a free, no-pitch way to walk through your specific numbers on a Google Meet. Free advice either way.