Section 179
Category: Deductions · Related form: Form 4562
An election to expense qualifying business property in the year placed in service, up to an annual dollar limit and taxable-income limit, instead of depreciating over time.
How Section 179 fits 2026 planning
Section 179 sits inside deduction planning — standard vs itemized choices, above-the-line adjustments, and Schedule A limits. For tax year 2026, US Tax Tools treats year-scoped constants (brackets, contribution limits, wage bases, credit schedules) as separate datasets — so explanations of Section 179 should be read with the same year selected in any linked calculator.
Category focus: Deductions. Readers usually land on this page while comparing a paycheck estimate, a credit phaseout, or a retirement contribution room figure that depends on understanding Section 179 first.
Worked example
Buying a $40,000 piece of equipment for an active business can often be fully expensed under Section 179 if limits and income tests are met.
Treat the example as a teaching sketch, not a filing position. Change filing status, state residency, or mid-year events and the same definition of Section 179 can produce a different cash outcome even when the glossary text stays the same.
What to watch for
Definitions of Section 179 can differ slightly across IRS publications, SSA rules, Marketplace subsidy worksheets, and state agencies. When two programs both say “income,” confirm which modification rules apply — MAGI for one credit is not always MAGI for another.
Legislation and inflation adjustments can move the dollar thresholds around Section 179 without renaming the concept. Prefer the effective date on the primary source (Rev. Proc., SSA notice, USDA table, or state DOR bulletin) over any blog summary — including this one if a later notice supersedes it.
On a filed return, Section 179 most often surfaces around Form 4562. Read the official IRS instructions for that form for the tax year you are filing — glossary pages summarize concepts; they do not replace line-by-line worksheets.
Next step
When you are ready to model numbers, open the Section 179 related calculator on US Tax Tools. Engines keep tax-year datasets separate so a 2025 habit does not silently reuse a 2026 constant.
Related reading: Tax insights for longer 2026 explainers, Methodology for how engines store cents and traces, and Disclaimer for educational-use limits.