Choosing Between Section 179 and Bonus Depreciation in 2026

A business that buys equipment faces a fundamental choice about when to claim its tax deduction: immediately in the year of purchase, or gradually over years through depreciation. Section 179 and bonus depreciation are the two mechanisms available for immediate expensing, but they work under different rules with different limits.

For tax years beginning in 2026, Section 179 allows a $2,560,000 immediate write-off, while 100% bonus depreciation—restored as permanent law by the One Big Beautiful Bill Act in July 2025—applies no dollar cap. The choice depends on a business’s income, the size and type of purchases, whether the equipment is new or used, and whether the owner wants to control which assets get expensed first.

Section 179’s fixed limit and income cap

Section 179 lets businesses deduct the full cost of qualifying equipment purchases in the year placed in service, up to $2,560,000 for tax years beginning in 2026. The deduction is not automatic; an owner must elect it on their tax return and specify which assets qualify. Qualifying property includes manufacturing equipment, business vehicles over 6,000 lbs GVWR, computers and technology systems, office furniture, off-the-shelf software, and certain building improvements. All equipment must be used more than 50 percent for business purposes and placed in service by the end of the tax year.

The deduction phases out once purchases exceed $4,090,000, declining dollar-for-dollar until it reaches zero at $6,650,000 in spending. A business that buys exactly $4.09 million in equipment has full access to the $2.56 million deduction. One that buys $4.5 million loses $410,000 of available deduction, reducing the usable amount to approximately $2.15 million. A business spending $6.65 million or more loses access to Section 179 entirely and must rely on other depreciation methods or bonus depreciation.

Section 179 also cannot exceed the business’s net taxable income for the year. If a business earned $300,000 in profit, a Section 179 deduction cannot exceed $300,000 even if $1 million in equipment was purchased. Unused portions carry forward to future tax years until the business has sufficient income to use them. This income limitation makes Section 179 most practical for profitable businesses or those coordinating purchases with projected annual earnings.

2026 deduction caps and phase-outs
Section 179 allows $2,560,000 in immediate write-offs, phasing out starting at $4,090,000 in total purchases and disappearing entirely at $6,650,000. Bonus depreciation has no dollar cap and applies at 100% for property acquired after January 19, 2025. Both can be used together by applying Section 179 first to priority assets, then bonus depreciation to remaining eligible property.

Bonus depreciation with no dollar cap or income limit

Bonus depreciation allows a business to deduct a percentage of qualifying asset costs in the first year, with no spending limit and no income restriction. The rate is now permanently set at 100 percent for property acquired on or after January 20, 2025, under the One Big Beautiful Bill Act, passed in July 2025. This applies to equipment and machinery with a recovery period of 20 years or less, computer software, qualified improvement property, and, beginning in tax years ending after July 4, 2025, qualified sound recording productions.

Unlike Section 179, bonus depreciation applies to both new and used equipment, provided it is the first use by the purchasing business. A business acquiring secondhand manufacturing machinery at a liquidation auction still qualifies. A sound recording production that begins principal recording in 2026 qualifies if the tax year ends after July 4, 2025. This expansion broadened the tool’s reach beyond new equipment purchases.

Bonus depreciation has no income limitation and can create a net operating loss, which carries forward to offset future years’ income. A startup that spent $2 million on equipment but had no revenue in its first year would generate a $2 million loss that reduces taxes owed in years two and beyond. This makes bonus depreciation particularly valuable for businesses with uneven cash flow, seasonal operations, or those making large upfront capital investments before generating revenue.

How Section 179 and bonus depreciation stack together

The IRS requires most businesses to apply Section 179 first, then bonus depreciation to remaining basis. This stacking maximizes total first-year deductions and accommodates different asset types and purchase sizes. Understanding the order matters: an owner should use Section 179 strategically on priority assets or up to the income limit, then capture remaining eligible costs under bonus depreciation.

Consider a business that bought $3 million in qualifying equipment in 2026 and had net income of $2.8 million. The owner could elect $2.56 million under Section 179 (the full annual limit, constrained only by the purchased amount, not the income). The remaining $440,000 qualifies for 100 percent bonus depreciation. Both deductions apply in the same tax year, allowing the business to write off the entire $3 million capital cost immediately rather than depreciating it over future years. In a 21 percent federal tax bracket, this generates approximately $630,000 in federal tax savings immediately.

For larger purchases, the phase-out structure shifts more of the deduction to bonus depreciation. A business spending $5 million in equipment in 2026 exceeds the $4.09 million threshold by $910,000, reducing the available Section 179 deduction to $1,650,000. The remaining $3,350,000 qualifies for 100 percent bonus depreciation, preserving a complete $5 million first-year write-off despite the Section 179 phase-out.

When to choose Section 179 over bonus depreciation

Section 179 is preferable when a business wants control over which assets receive immediate expensing. An owner can elect it on specific priority equipment—such as essential production machinery or vehicles critical to operations—and leave lower-priority items like office furniture to depreciate normally. This selective approach manages the tax deduction impact year to year.

Section 179 also appeals to profitable businesses that cannot absorb large operating losses. A consulting firm earning $600,000 annually avoids creating a net loss by using Section 179, which caps deductions to income.

For smaller purchases under $2.56 million, Section 179 alone often suffices and requires less tax planning complexity. The owner makes a simple election on Form 4562, specifies the assets, and claims the deduction. No cost segregation study, sophisticated loss-tracking, or multi-year carryforward strategies are necessary.

Bonus depreciation has no income limitation and can create a net operating loss, which carries forward to offset future years’ income.

When bonus depreciation makes sense

Bonus depreciation is the better choice for large equipment purchases exceeding the Section 179 phase-out threshold of $4.09 million. It allows the same immediate write-off with no upper limit. A manufacturing business that invests $8 million in new production equipment receives a full $8 million deduction in the first year under bonus depreciation, versus zero under Section 179 due to the phase-out.

Bonus depreciation also suits businesses with volatile or cyclical income. A construction company might have $1.5 million in taxable income one year and $800,000 the next. Section 179 would be limited to $1.5 million in the high-income year and $800,000 in the low-income year, constraining equipment purchases to coincide with income. Bonus depreciation’s lack of income limitation means the deduction applies regardless of that year’s profit, and any excess loss carries forward without restriction.

Filing, documentation, and cost segregation

Claiming either deduction requires careful timing and documentation. Property must be acquired—meaning purchased or ordered under a binding contract—on or after the required date and placed in service by year-end. For bonus depreciation, property acquired under a written binding contract entered into before January 20, 2025 generally does not qualify for the 100 percent rate. This acquisition date, not the placed-in-service date, determines eligibility.

Both deductions are claimed on Form 4562, which requires listing each asset or asset class, its cost, the acquisition date, and the placed-in-service date. Invoices, purchase agreements, installation records, and support for any elections must be retained. The IRS permits businesses to opt out of bonus depreciation entirely for any asset class, allowing more selective use.

For real estate and building-related investments, a cost segregation study can unlock additional deductions. This specialized accounting analysis reclassifies building components into shorter-life categories eligible for Section 179 or bonus depreciation, converting what would normally depreciate over 39 years into five-year or seven-year property. A small business expanding facilities can sometimes accelerate deductions significantly through cost segregation, though professional analysis is required.

Photo: Shixart1985 · CC BY 2.0 · via Wikimedia Commons