Section 179 Vehicle Deduction Calculator

Section 179 lets you expense a qualifying business vehicle in the year it is placed in service, instead of depreciating it over six years. But the headline "write off 100% of your truck" that dominates this topic skips three limits that decide the real number: the 6,000-lb GVWR line, the business-use share, and the fact that you only get to pick one depreciation method per vehicle. The calculator above estimates your first-year deduction and shows the working. Every figure here is verified against irs.gov for 2026 — and it is educational, an estimate, confirm with your tax professional.

What Section 179 does — timing, not magic

IRC §179 lets you elect to expense qualifying property in the year it is placed in service rather than recovering it through depreciation over the MACRS recovery period. "Placed in service" means the vehicle is ready and available for its intended business use — not the date you paid or ordered it. Buy a van on 31 December and take delivery in January, and it is a next-year deduction.

The mental model that keeps you out of trouble: §179 accelerates a deduction you would eventually get anyway. It moves depreciation forward; it does not create free money. When people say a truck "paid for itself in tax savings," they are describing a timing benefit — and, since the One Big Beautiful Bill Act (P.L. 119-21) reinstated 100% bonus depreciation for property placed in service after 19 January 2025, that timing benefit is currently at its most generous for heavy vehicles.

The three limits that kill most "100% write-off" claims

Before you count on a full write-off, three limits have to be checked in order:

1. Business use must exceed 50%. At exactly 50% or below you cannot elect §179 or bonus depreciation on the vehicle at all — you are limited to straight-line depreciation. This is a cliff, not a slope.
2. The 6,000-lb GVWR line. Passenger autos under 6,000 lb GVWR are "listed property" hit by the §280F luxury-auto caps — for 2026 the first-year cap is $20,300 with bonus depreciation (Rev. Proc. 2026-15). Heavy SUVs over 6,000 lb GVWR get a higher but still separate §179 cap of $32,000 for 2026 (§179(b)(5)). Cargo vans, pickups with a bed of at least six feet, and vehicles with no seating behind the driver escape the SUV cap entirely.
3. You still only deduct the business-use share. 80% business use on a $70,000 truck is not a $70,000 deduction — it is a deduction built on a $56,000 basis, and the caps above apply to that.

Figures verified against IRS Pub 946 and Rev. Proc. 2026-15. Estimates — confirm with your tax professional.

Recapture — the part the write-off videos skip

If your business use later drops to 50% or less during the recovery period, you have to recapture the excess §179 benefit as ordinary income in that later year (§179(d)(10)). In plain terms: if the truck becomes mostly personal in year two, part of the year-one deduction comes back and lands on that year's return. This is exactly why business-use percentage needs a contemporaneous mileage record, not a year-end estimate — and why the "buy a G-Wagon, write it all off" advice is dangerous when the vehicle isn't genuinely a business vehicle.

Section 179 vs the standard mileage rate — pick a lane

You cannot claim §179 (or any depreciation) on a vehicle and also use the standard mileage rate for it — the standard rate already bakes in a depreciation component (Rev. Proc. 2010-51). Electing the standard mileage rate in the first year also locks §179 and MACRS depreciation out of that vehicle for later years. So the vehicle-deduction decision is really a fork: the actual-expense method (which is where §179 and bonus live) or the standard mileage rate — not both.

Which one wins depends on the vehicle's cost, how many business miles you drive, and how long you keep it. We do not re-answer that here — the full method comparison lives on standard mileage vs actual expenses, and the per-mile math lives on the mileage calculator. Section 179 is the actual-expense lane, front-loaded.

What you need on file if the IRS asks

Vehicles are listed property under §274(d), which means strict substantiation: mileage and business purpose need real records, and the Cohan estimation rule does not rescue a missing log. A defensible file looks like this:

• The purchase invoice — price and date placed in service.
• GVWR evidence — the door-jamb sticker or the manufacturer spec, to prove which side of the 6,000-lb line you are on.
• A mileage record with business purpose — date, miles, destination, reason.
• The operating-cost receipts — fuel, repairs, insurance behind the actual-expense figures.

This is the unglamorous part, and it is where spend capture earns its keep: ExpenseBot pulls the purchase invoice and the running fuel, repair, and insurance receipts out of your Gmail into a Google Sheet you own, so the actual-expense side of a vehicle deduction has a paper trail instead of a shoebox. It captures the documents — the §179 election and the depreciation schedule stay with you and your tax pro.

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