Standard Mileage vs Actual Expenses: Which One Writes Off More of Your Car.

Every tax program asks the same question about a business vehicle, and almost nobody answers it on purpose. Standard mileage vs actual expenses? The program runs both numbers, the owner takes the bigger one, and that is the whole decision. The trouble is that the bigger number in the first year is often the smaller number over the life of the car, and the choice made that first year is usually the only choice you get.

The rule sits in Publication 463. To use the standard mileage rate on a car you own, you have to choose it in the first year the car is available for use in your business, and you make that choice by the due date of the return, extensions included. There is no late election, and no second look in year three when you notice the depreciation schedule going nowhere.

What makes this worth real money is the asymmetry. Start with the mileage rate and you can switch to actual expenses in any later year: you estimate the car's remaining useful life, depreciate what is left straight line, and live with the IRC §280F caps. Go the other way and the door is welded shut. Rev. Proc. 2019-46, §4.05 bars the business standard mileage rate on any automobile for which you claimed a §179 deduction, the additional first-year depreciation allowance under §168(k), or any method under the Modified Accelerated Cost Recovery System. One year of accelerated depreciation ends the conversation.

The second-opinion reviews I do almost never show a decision here. They show drift. Actual expenses one year, mileage the next, a depreciation schedule that restarts for no reason I can find in the file. No single line is big enough to amend over, and I usually tell people not to bother. The cost is that nobody ever ran the comparison, and by the time they ask me the better method is already off the table.

The IRS set the 2026 rates in Notice 2026-10 last December: 72.5 cents a mile for business, 20.5 cents for medical and moving, 14 cents for charity. Then fuel prices moved. Announcement 2026-11, published at 2026-29 I.R.B. 49 on July 13, 2026, raised the business rate to 76 cents and the medical and moving rate to 23.5 cents for miles driven on or after July 1, 2026. The charitable rate did not budge, because §170(i) fixes it at 14 cents in the statute instead of indexing it.

So a 2026 return needs a June 30 odometer reading. One annual total can't be split after the fact without guessing, and a guess is not substantiation under §274(d). If you don't have the reading, rebuild the split now from your calendar or your mileage app's trip history, while the year is still recoverable. Rebuilding it during an exam is a different experience.

One more thing the mileage rate quietly does: §4.04 of Rev. Proc. 2019-46 makes you reduce the car's basis by the depreciation baked into the rate, which Notice 2026-10 sets at 35 cents a mile for 2026. The mileage method is depreciating the car. It just does it off the page, and the bill arrives as gain when you sell.

Actual expenses wins 2026 by $7,211, which is why almost everyone takes it. Over five years the mileage rate comes out $13,826 ahead. At a 24% federal bracket plus self-employment tax, that gap is worth roughly $5,000 of federal tax before any state tax, and electing bonus depreciation in 2026 is the act that gives it away. Parking, tolls, and the business share of the car loan interest are deductible under either method, so they don't break the tie. The personal side of that loan interest follows its own new rule, which I covered in the $10,000 car loan interest deduction.

§280F(b)(2) is the second reason to be careful with a big first-year write-off. If business use of the vehicle falls to 50% or less in any year inside the recovery period, the depreciation you claimed above what straight line under the alternative depreciation system would have allowed is recaptured as ordinary income. It happens in the year the use drops, with no sale involved, computed in Part IV of Form 4797 and reported back on the same schedule that took the deduction.

The path there is ordinary. An owner buys a vehicle in 2026, bonuses the business share, then takes a W-2 job in 2028 and the car goes mostly personal. The safe harbor in Rev. Proc. 2019-13 stops applying, part of the 2026 deduction returns as 2028 ordinary income, and the mileage rate is still unavailable. That is the version I see every December, when the purchase is being made for the deduction rather than for the work.

1. 01Passenger automobile rated at 6,000 pounds GVWR or less, driven more than about 12,000 business miles a year: start with the standard mileage rate. §280F caps the depreciation anyway, so the first-year number you are giving up is smaller than the software makes it look.
2. 02Rated over 6,000 pounds GVWR, expensive, and driven relatively few business miles: actual expenses with bonus depreciation wins outright, and the mileage rate was never worth much. That math is in the Section 179 deduction for vehicles over 6,000 pounds.
3. 03Any real chance business use drops to 50% or less within six years: skip §179 and bonus depreciation. The recapture is worse than the deferral.
4. 04S corp owner with the car titled in your own name: neither method belongs on the 1120-S. Reimburse yourself at the standard mileage rate through an accountable plan.
5. 05Either way, keep the log. §274(d) makes vehicle expenses one of the few deductions where the records are a condition of the deduction and not just evidence for it.

If I had to pick one default for a sole proprietor driving a normally priced car for work, it's the mileage rate in year one, every time. It deducts more over the life of most cars, it keeps the switch to actual expenses available if the car turns out to be expensive, and it costs you nothing but a first-year head start you were going to earn back anyway.