Enter a truck's purchase price, your business-use %, and your marginal tax rate to estimate your first-year write-off and tax savings. For 2026, 100% bonus depreciation is back (2025 OBBBA) on top of a $2.56M Section 179 limit — so a qualifying business truck can usually be expensed in full the first year.
Estimate only, not tax advice. Assumes the truck is placed in service in 2026 and (for the full first-year write-off) used more than 50% for business. Your real result depends on your income, entity type, state conformity, and other purchases — confirm with your CPA.
TruckMargin Pro saves each truck's purchase price, depreciation, and filing dates, and exports a clean PDF/CSV at tax time — $9/mo founding rate.
See Pro →Both let you deduct the cost of a truck in the first year instead of spreading it over several years, and for a qualifying heavy truck in 2026 they reach the same place: a 100% first-year write-off. They just get there differently.
Section 179 is an election to expense equipment up front. For 2026 you can expense up to $2,560,000 of qualifying property, with the benefit phasing out dollar-for-dollar once your total equipment purchases pass $4,090,000 (gone entirely at $6,650,000). Section 179 can't create a loss — it's limited to your business income. Bonus depreciation, restored to 100% by the 2025 One Big Beautiful Bill Act for property placed in service after January 19, 2025, has no dollar cap and can create a loss. Most owner-operators use Section 179 first, then let 100% bonus depreciation clean up anything left — so a single truck is fully deductible either way.
| Rule | 2026 figure | Notes |
|---|---|---|
| Section 179 deduction limit | $2,560,000 | Total for all qualifying property in the year |
| Section 179 phase-out starts | $4,090,000 | Reduces dollar-for-dollar above this |
| Section 179 fully phased out | $6,650,000 | No 179 above this spend |
| Bonus depreciation rate | 100% | Property placed in service after Jan 19, 2025 (OBBBA) |
| Business-use minimum | Over 50% | Required for 179 & bonus; deduction prorated by use |
Source: IRS Section 179 rules and the One Big Beautiful Bill Act (2025). Limits are indexed and can change — verify for your tax year.
You may have heard first-year vehicle write-offs are capped. That cap applies to passenger vehicles and SUVs between 6,000 and 14,000 lbs. A semi tractor — GVWR over 14,000 lbs — is treated as equipment, not a passenger vehicle, so it isn't subject to that limit. Day cabs, sleepers, dumps, and other Class 7–8 vocational trucks are all in the clear; the whole business-use cost is eligible. Lighter pickups and vans in the 6,000–14,000 lb band still qualify for Section 179 but run into the SUV first-year limit, which is why the calculator asks for the truck class.
Yes. A semi (GVWR over 14,000 lbs) used more than 50% for business is treated as equipment, so it qualifies for the full Section 179 deduction with no SUV cap. The 2026 limit is $2,560,000 — well above any single truck — so the business-use portion is generally deductible in year one.
Yes. The 2025 One Big Beautiful Bill Act permanently restored 100% bonus depreciation for qualifying property acquired and placed in service after January 19, 2025. It applies for the full 2026 tax year and, unlike Section 179, has no dollar cap and can create a loss.
Yes. Both Section 179 and, under the OBBBA, 100% bonus depreciation apply to used trucks, as long as it's the first time you place that truck in service (not bought from a related party). New and used are treated the same for the first-year write-off.
Use your combined marginal rate on the last dollars of business income — federal income tax plus, for a sole-proprietor or single-member LLC owner-operator, the ~15.3% self-employment tax on the reduced income, plus any state tax. Many owner-operators land somewhere around 22–35% combined. The default 24% is a middle-of-the-road estimate; enter your own for a closer figure.
First-year deduction = purchase price × business-use %, assuming a qualifying heavy truck (GVWR over 14,000 lbs) placed in service in 2026 and used more than 50% for business, which is fully expensable via Section 179 (2026 limit $2,560,000) and/or 100% bonus depreciation. Estimated tax savings = deduction × your marginal rate; effective cost = price − savings. Lighter 6,000–14,000 lb vehicles are shown with a note that the SUV first-year cap may apply. Sources: Section179.org 2026 limits and IRS guidance on the One Big Beautiful Bill Act (2025) restoring 100% bonus depreciation. Last updated July 2026. Estimate for planning only — not tax advice; confirm with your CPA. Built by TruckMargin.