Home Office and Vehicle Deductions: What You Can Actually Claim

If you work from home or drive for business, you are likely leaving real deductions on the table — or claiming them in a way that will not survive an IRS review. Home office and vehicle deductions are two of the most valuable write-offs available to small-business owners, but they are also two of the most commonly mishandled. Here is how to get both right.

What Actually Counts as a Home Office

The IRS does not care that you sometimes answer emails from your couch. To claim a home office deduction, the space must be used exclusively and regularly as your principal place of business or a place where you meet clients or customers.

"Exclusively" is the word that trips people up. If your home office is also a guest bedroom, a kid's homework area, or your TV room, it does not qualify. The space has to be used only for business. There is no partial credit for "mostly business."

Regular use means you use the space consistently for business — not just once in a while. Working in that room every weekday for your business counts.

Two Ways to Calculate the Deduction

Once you have a qualifying space, you have two calculation options.

The simplified method lets you multiply your office square footage by a flat rate set by the IRS, up to a maximum of 300 square feet. It is straightforward and requires minimal record-keeping. You do not need to save utility bills or track home maintenance costs.

The actual expense method requires more work but can produce a larger deduction. You calculate what percentage of your home's total square footage the office occupies, then apply that percentage to your combined home expenses — mortgage interest, property taxes, utilities, insurance, repairs, and depreciation.

Which method wins depends on your home size, office size, and total home costs. A small office in an expensive home often does better with actual expenses. If simplicity matters more than squeezing out every dollar, the simplified method is hard to beat.

Vehicle Deductions: Choose Your Method Carefully

If you drive a personal vehicle for business, you can deduct the business portion of your driving costs through one of two methods.

The standard mileage rate lets you multiply your business miles by a rate the IRS sets each year. That single rate is designed to cover gas, maintenance, depreciation, insurance, and registration. You just need a mileage log — no fuel receipts required.

The actual expense method means tracking every dollar spent on the vehicle — fuel, oil changes, tires, insurance, registration, repairs, loan interest, and depreciation — then multiplying the total by the percentage of miles driven for business.

Here is the catch: if you choose actual expenses in the first year you use the car for business, you generally cannot switch to the standard mileage rate for that same vehicle in later years. If you start with the mileage rate, you can switch to actual expenses later with some restrictions. Pick carefully that first year.

Track Mileage as You Go

No matter which vehicle method you use, you need a mileage log. The IRS wants to see the date, miles driven, business purpose, and destination for each trip.

A notebook in the glove box works. A mileage tracking app works better for most people. What does not work is reconstructing a year of driving from memory or bank statements at tax time. If you get audited, a backfilled log will not hold up.

Track every business trip as it happens. If you use the standard mileage rate, this log is essentially your entire documentation for the deduction.

Keep Records That Hold Up

For home office deductions under the actual method, keep utility bills, mortgage statements, property tax records, and any home repair receipts. For the simplified method, document your office square footage and your home's total square footage.

For vehicle deductions, keep your mileage log plus fuel receipts, maintenance records, and insurance bills if you use actual expenses. With the standard mileage rate, the mileage log is the key document.

Keep everything for at least three years after filing. If the IRS questions your deductions, you want organized records — not a scramble.

None of this is complicated once you have a system in place. If tracking deductions, categorization, and documentation sounds like more than you want to manage on top of running your business, TwoDayBooks can handle the bookkeeping so your records stay clean and your deductions are backed up.