Calculate first-year write-offs, heavy vehicle exemptions, and cash tax reduction
FAQ last updated October 2026, reflecting 2026 tax-year rules.
The twelve questions buyers ask most — answered in plain English, with the 2026 limits baked in. For the three basics (what qualifies, the 50% rule, the December 31 deadline), see the quick FAQ on the calculator page. For how each number on the calculator is derived, read the methodology page.
Yes. Both Section 179 and bonus depreciation apply to used vehicles, as long as the vehicle's first use is by you — the taxpayer claiming the deduction. You can't take a truck you already drove personally, convert it to business use, and claim a first-year write-off; but a genuinely new-to-you used vehicle qualifies exactly like a new one. The 2026 limits — including the $32,000 heavy-SUV cap — apply identically.
Related: Section 179 on used vehicles
No. On a lease, the leasing company owns the vehicle and claims the depreciation — not the lessee. You deduct your lease payments as a business expense instead (subject to the same business-use percentage), and bonus depreciation is off the table for you too. If first-year expensing is the goal, buying or financing is the route.
Related: Section 179 on leased vehicles
Then the vehicle doesn't qualify. The rule requires more than 50% business use — 50.0% on the nose is not enough. At or below 50%, the vehicle must be depreciated on the straight-line MACRS schedule with no Section 179 and no bonus depreciation. This is why a contemporaneous mileage log matters: estimates won't survive an audit.
The deduction can be recaptured. If business use falls to 50% or less in a later year, or you sell the vehicle before it's fully depreciated, part of the Section 179 deduction is added back to your taxable income as ordinary income, and depreciation recapture rules apply to the bonus portion. Plan to keep the vehicle in majority-business service for its depreciable life — or run the recapture math with your CPA before selling.
Related: Depreciation recapture on trucks
Yes — and this is exactly how the calculator works. Section 179 is applied first (subject to its caps, like the $32,000 heavy-SUV limit), and bonus depreciation applies to whatever basis remains. For a heavy truck, Section 179 usually covers everything; for a heavy SUV, the cap leaves a remainder that 100% bonus depreciation picks up; for passenger vehicles, the luxury-auto limits cap the combined total at $20,300 for 2026.
Related: Bonus depreciation vs. Section 179
Maybe — and maybe not. Many states decouple from federal bonus depreciation, requiring you to add the bonus amount back to state income and depreciate it on a slower schedule. A few also limit Section 179. The federal estimate on our calculator doesn't change, but your state-side benefit can be much smaller.
Related: 50-state conformity hub
Three things, at minimum:
Section 179 audits live and die on the mileage log.
On the VIN safety label inside the driver's door jamb — not the brochure or the manufacturer's website. GVWR (Gross Vehicle Weight Rating) is the maximum loaded weight the manufacturer rates the vehicle for, and it's the number the IRS uses. This is what determines whether you get the over-6,000-lb heavy-vehicle treatment.
Related: What is GVWR? and qualifying vehicles list
The vehicle must be purchased, delivered, and placed in service by midnight on December 31 of the tax year. "Placed in service" means available and ready for business use — ordering a truck in December that arrives in January doesn't count. If you're buying in Q4, confirm the delivery date in writing before relying on the deduction.
For sole proprietors and partners, yes — a Section 179 or bonus depreciation deduction on Schedule C lowers your net earnings from self-employment, which lowers both your income tax and your self-employment tax. For S-corporation shareholders, the deduction flows through against income tax but doesn't touch your W-2 wages. Your entity type changes the math — another item to confirm with a CPA.
Section 179 is limited to your business's taxable income — you can't create a loss with it. The unused portion carries forward to future years, so it's not lost. Bonus depreciation has no income limit and can create or increase a loss. This is one of the practical reasons CPAs sometimes prefer bonus over Section 179 in low-income years.
Related: 2026 deduction limits
No. The deduction is based on the purchase price and placed-in-service date, not how you paid. A financed $68,000 truck gets the same first-year deduction as a cash-bought one; loan interest is separately deductible as a business expense.
Related: Financing vs. tax savings calculator
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