Section 179 Business Vehicle Tax Estimator

Calculate first-year write-offs, heavy vehicle exemptions, and cash tax reduction

Walkthrough published October 2026, using 2026 tax-year limits. Figures are illustrations, not tax advice.

What This Walkthrough Shows

Tax rules are easier to understand when you can follow the money. Below, three realistic buyers run their purchases through the vehicle write-off calculator — a work truck, a heavy SUV, and a passenger crossover. Each scenario uses the same five inputs (price, vehicle class, business-use percentage, tax rate) and shows exactly how the result is built.

The punchline is visible before you read a word: the vehicle's class matters more than its price. A $75,000 SUV and a $68,000 truck don't get treated remotely the same way.

Scenario 1 — The Work Truck: Full Expensing

A self-employed general contractor buys a 2026 Ford F-150 SuperCrew, 6.5-ft bed, GVWR 7,050 lbs, for $68,000.

The truck clears 6,000 lbs GVWR and has a 6-foot-plus bed, so it lands in the calculator's heavy truck class — exempt from the SUV cap. The contractor drives it 80% for business (job sites, supply runs) and 20% personal. Her combined marginal tax rate is 32%.

Purchase price: $68,000
Vehicle class: Heavy truck (>6,000 lbs GVWR, 6-ft+ bed)
Business use: 80%
Combined marginal tax rate: 32%

Business basis = $68,000 × 80% = $54,400
Section 179 = $54,400 (full basis — no SUV cap applies)
Bonus depreciation = $0 (nothing left to depreciate)
Total first-year deduction = $54,400
Tax savings = $54,400 × 32% = $17,408
Effective net cost = $68,000 − $17,408 = $50,592

Takeaway: Nearly a quarter of the truck's price comes back as first-year tax savings. For cash-flow context: financed at 7% over 72 months, that truck costs roughly $1,160/month — so the $17,408 first-year benefit covers about 15 months of payments. (See the financing vs. tax savings calculator to model this yourself.)

Scenario 2 — The Heavy SUV: Cap, Then Bonus

A real-estate investor buys a 2026 Chevrolet Tahoe, GVWR 7,600 lbs, for $75,000 — 100% business use.

The Tahoe clears 6,000 lbs but has no qualifying cargo bed, so it's a heavy SUV: Section 179 is capped at $32,000 for 2026. But the remaining basis still qualifies for 100% bonus depreciation — heavy SUVs over 6,000 lbs GVWR are not subject to the passenger-vehicle luxury limits on the bonus portion. His combined marginal rate is 35%.

Purchase price: $75,000
Vehicle class: Heavy SUV (6,000–14,000 lbs GVWR)
Business use: 100%
Combined marginal tax rate: 35%

Business basis = $75,000 × 100% = $75,000
Section 179 = $32,000 (capped)
Bonus depreciation = $75,000 − $32,000 = $43,000
Total first-year deduction = $32,000 + $43,000 = $75,000
Tax savings = $75,000 × 35% = $26,250
Effective net cost = $75,000 − $26,250 = $48,750

Takeaway: The $32,000 SUV cap sounds restrictive, but bonus depreciation picks up the rest — the investor still deducts the full $75,000 in year one. The cap only matters when stacking strategies get more complex. More on the interplay in our heavy SUV rules guide.

Scenario 3 — The Crossover: Luxury Limits Bite

A freelance consultant buys a 2026 Toyota RAV4 Hybrid, GVWR 4,610 lbs, for $42,000 — 100% business use.

Under 6,000 lbs GVWR, the RAV4 is a passenger vehicle subject to the §280F luxury auto limits: $12,200 of Section 179 plus $8,100 of additional first-year bonus — a $20,300 total first-year ceiling for 2026, no matter what the vehicle costs. Her combined marginal rate is 35%.

Purchase price: $42,000
Vehicle class: Passenger car / crossover (<6,000 lbs GVWR)
Business use: 100%
Combined marginal tax rate: 35%

Business basis = $42,000 × 100% = $42,000
Total first-year deduction = min($42,000, $20,300 cap) = $20,300
of which Section 179 = $12,200, bonus = $8,100
Tax savings = $20,300 × 35% = $7,105
Effective net cost = $42,000 − $7,105 = $34,895
Remaining basis = $42,000 − $20,300 = $21,700 (depreciated over 5-year MACRS)

Takeaway: Same 35% rate as Scenario 2, but a fraction of the savings — the luxury limits, not the tax rate, are doing the work. The remaining $21,700 isn't lost; it depreciates over the standard 5-year MACRS schedule. This is why buyers focused on first-year deductions gravitate toward vehicles over 6,000 lbs.

Side-by-Side Comparison

	Work Truck (F-150)	Heavy SUV (Tahoe)	Crossover (RAV4)
Purchase price	$68,000	$75,000	$42,000
Business use	80%	100%	100%
Section 179	$54,400	$32,000	$12,200
Bonus depreciation	$0	$43,000	$8,100
Total first-year deduction	$54,400	$75,000	$20,300
Tax savings	$17,408	$26,250	$7,105
Effective net cost	$50,592	$48,750	$34,895

Notice that Scenario 1's truck — the cheapest of the heavy pair — leaves the most basis on the table in percentage terms only because of the 80% business use. At 100% business use, that same $68,000 truck would produce a $68,000 deduction. Business-use percentage is a multiplier on everything.

How to Run Your Own Numbers

Find your GVWR on the driver's door-jamb VIN label — not the brochure, the label. This decides your vehicle class.
Be honest about business use. Commuting from home to a regular workplace doesn't count. Keep a contemporaneous mileage log from day one.
Use your marginal rate, federal bracket plus state income tax — not your effective rate.
Buy before December 31. "Placed in service" means delivered and available for business use, not ordered.

Full details on how the calculator applies each rule are in our methodology page, and answers to the questions buyers ask most are in the Section 179 FAQ.

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How the Math Works →

Formulas, limits, and assumptions.

Financing vs. Savings →

Compare the loan against the tax benefit.