Writing Off a Business Vehicle: The 6,000-Pound Rule and the Luxury-Car Trap

Every fall, the same question lands in my inbox: “If I buy a truck before year-end, do I get to write the whole thing off?” Sometimes yes. Sometimes you deduct about a third of it this year and the rest dribbles out over six. The difference usually comes down to one number stamped on the driver’s-side door jamb — the vehicle’s weight.

Here’s the rule almost nobody explains in plain English: the IRS treats a vehicle’s “GVWR” — its gross vehicle weight rating, basically the maximum loaded weight the manufacturer says it can carry — as the dividing line. Cross 6,000 pounds and a different, far more generous set of write-off rules applies.

Under 6,000 pounds: the luxury-car cap

Buy a normal sedan or a small SUV for the business and you run straight into what the law actually calls the “luxury auto” limits — a cap on how much depreciation you can take each year, no matter how much the car cost. For a vehicle placed in service now, that first-year deduction tops out around $20,200 even if you elect bonus depreciation, and closer to $12,200 without it.

So you spend $55,000 on a sedan, use it 100% for business, and you’re still only writing off about twenty grand the first year. The rest crawls out over the next five-plus years. Annoying, but that’s how the cap works.

Over 6,000 pounds: the rules open up

Now put a vehicle with a GVWR over 6,000 pounds in service — most full-size pickups, cargo vans, and the heavier SUVs — and the luxury-car cap doesn’t apply. Section 179 lets you expense up to about $31,300 of a heavy SUV in year one, and because 100% bonus depreciation is permanent again for property placed in service after January 19, 2025, you can deduct the remaining basis on top of that with no separate dollar cap.

Translation: a qualifying $70,000 work truck used entirely for business can be a near-total write-off the year you put it to work, instead of a six-year trickle. That’s the gap people are talking about when they mention the “6,000-pound rule.” (This is the same engine behind the bonus-depreciation rules I broke down in 100% Bonus Depreciation Is Permanent Again — vehicles just have their own weight-based on-ramp.)

The percentage nobody wants to hear about

All of this rides on one word: business use. A vehicle is what the law calls “listed property,” which is a polite way of saying the burden is on you to prove how much you actually drove it for the business. Use the truck 70% for work and 30% for life, and you deduct 70%. Drop business use below 50% in a later year and the IRS can claw back deductions you already took.

So keep a mileage log. A real one — dates, miles, where you went and why — not a number you reconstruct in April from memory. This is the single most common thing that turns a clean vehicle deduction into a disallowed one in an audit. We recommend using one of the many highly rated phone-based apps to track your mileage. MileIQ and TripLog are just a couple that are easy to use.

Mileage vs. actual: pick the right method

Two ways to deduct a vehicle, and you generally commit to a lane early:

The “standard mileage” method is dead simple — multiply your business miles by the IRS rate, which is 72.5 cents a mile for 2026. Drive 12,000 business miles and that’s $8,700, no receipts for gas or repairs required.

The “actual expense” method adds up real costs — gas, insurance, repairs, and depreciation (where Section 179 and bonus live) — and deducts the business-use share. That’s where the big first-year heavy-vehicle numbers come from.

The rough rule: high miles and a cheaper vehicle usually favor mileage; an expensive vehicle you don’t put many miles on usually favors actual. But the choice locks in consequences for the life of the car, so it’s worth getting right the first time, not guessing.

Don’t let the deduction buy the truck

Here’s the part the dealership won’t tell you. A write-off lowers your taxable income — it does not cut your tax bill dollar-for-dollar. Spend $70,000 on a truck and you might save $20,000–$25,000 in tax. You’re still out the other forty-plus thousand. If you needed the truck, that’s a real discount. If you bought it for the deduction, you just spent seventy grand to save twenty. That’s not a strategy.

Buy the vehicle the business actually needs, in the year that lines up with a high-income year, and document it cleanly. That’s the whole game.

This article is general information, not tax advice. Vehicle write-offs depend on your business-use percentage, your entity, the exact vehicle, and how your state conforms to the federal rules — let's look at your specific situation before you buy or file.