Every year, drivers who use a personal vehicle for work leave money on the table simply because they don't know which trips actually qualify as a business expense. The rules aren't as fuzzy as they seem — the IRS draws a fairly clear line between the miles you can write off and the ones you can't. The trick is understanding where the workday begins and ends in the eyes of the tax code.
This guide walks through exactly what counts, what doesn't, and how to keep records that will survive scrutiny if you're ever asked to prove it.
The Core Idea: Business Purpose, Not Just Distance
The mileage deduction exists for people who put their own car to work. If you're self-employed and use your personal vehicle for business purposes, you can deduct the car-related costs tied to that use. The deduction isn't about how far you drive — it's about why you drive.
A trip qualifies when its primary reason is to conduct business: meeting a client, picking up supplies, traveling between job sites, or running an errand that directly serves your work. A trip does not qualify when it's fundamentally personal, even if you happen to think about work along the way or make a quick business call from the parking lot.
That distinction — purpose over distance — is the foundation everything else rests on.
The Commuting Rule: Why Your First and Last Trips Usually Don't Count
Here's the piece that surprises most people. The drive between your home and your regular place of work is considered a commute, and commuting is a personal expense. It doesn't matter how long the drive is or how heavy the traffic gets — the IRS treats it as the cost of choosing where to live relative to where you work.
So if you leave your house in the morning, drive to your office or usual work location, and drive home again at night, neither leg is deductible. Those bookend trips are simply part of daily life.
Where it gets interesting is what happens between those two points.
What Actually Counts as a Deductible Business Mile
Once you've reached your first business stop of the day, the miles you drive to get to additional business stops generally do count. In practice, only trips driven between your first business stop and subsequent stops can be deducted as a mileage expense.
Think of your workday as a chain of destinations. The links in the middle of that chain — the drives from one business location to the next — are the deductible ones. Here are the kinds of trips that typically qualify:
- Travel between two work locations — driving from your office to a client's site, or from one job to another.
- Client and customer visits — going to meet someone for work purposes, whether it's a sales call or a service appointment.
- Errands for the business — trips to buy supplies, drop off equipment, visit the bank for business banking, or ship products.
- Temporary work sites — driving to a location that isn't your regular workplace for a short-term assignment.
- Professional appointments — meetings with an accountant, attorney, or other advisor on business matters.
The common thread is that each of these trips serves the business directly and happens after your workday's business activity has begun.
The Home Office Exception That Changes Everything
There's one situation where the commuting rule flips almost entirely: when your home is your principal place of business.
If you legitimately run your business out of a home office — meaning it's your main location for doing work and managing operations — then your home effectively becomes your first business stop. In that case, the drive from your home office to a client, a supplier, or any other work location can count as a business mile, because you're traveling between business destinations rather than commuting from home to a separate workplace.
This is a major advantage for freelancers, consultants, and small business owners who work from home. But the home office has to be real and qualify under the rules, not just a laptop on the kitchen table you use occasionally.
Trips That Don't Make the Cut
It helps to be just as clear about what you can't deduct, because claiming personal miles is one of the fastest ways to invite trouble. The following generally do not qualify:
- Your regular commute — home to your usual workplace and back, as covered above.
- Personal errands — the grocery store, school pickups, the gym, or the doctor.
- Detours for personal reasons — if you stop for something personal in the middle of a business trip, that added mileage isn't deductible.
- Mixed trips where personal is the main purpose — if the real reason for the drive is personal and you tack on a small work task, the trip stays personal.
When a single drive mixes business and personal purposes, you generally have to separate out and deduct only the portion that was genuinely for business.
How to Calculate the Deduction
Once you know which miles count, you have two ways to turn them into a deduction.
The Standard Mileage Rate
The simpler method multiplies your qualifying business miles by a set per-mile rate published by the IRS each year. This rate is designed to cover gas, wear and tear, maintenance, insurance, and depreciation all in one number. You track your business miles, apply the rate, and you have your deduction. Most people find this approach far less work.
The Actual Expense Method
Alternatively, you can total up the real costs of operating your vehicle — fuel, oil changes, repairs, insurance, registration, depreciation, and more — then deduct the percentage that corresponds to your business use. If 40% of your total miles were for business, you deduct 40% of those costs. This method can produce a bigger deduction for expensive vehicles, but it demands much more detailed record-keeping.
Whichever method you choose, you still need to know your business-versus-personal mileage split, which brings us to the part that matters most in practice.
Records Are What Make the Deduction Real
A deduction you can't prove is a deduction you can lose. If your return is ever questioned, the burden is on you to show that the miles you claimed were genuinely for business. That means keeping a contemporaneous log — recorded at or near the time of the trip, not reconstructed from memory months later.
A solid mileage record should capture:
- The date of each trip
- Your starting point and destination
- The business purpose of the trip
- The miles driven
You'll also want your total annual mileage so you can calculate the business-use percentage. This is where a dedicated tool earns its keep — apps like Rienly can log your trips automatically and keep your vehicle's maintenance records in one place, which spares you the shoebox-of-receipts scramble come tax season.
Whether you use an app or a notebook, consistency is what counts. A clean, ongoing log is worth far more than a heroic weekend of trying to remember where you drove all year.
A Simple Way to Decide in the Moment
When you're not sure whether a trip qualifies, ask yourself two questions:
- Have I already started my business day at a first business stop? If your home office counts as that first stop, you've cleared this hurdle immediately.
- Is the primary purpose of this specific drive to serve my business? If the honest answer is yes, and it's not your regular commute or a personal errand, the miles most likely count.
Run trips through that filter and log them as you go, and by year's end you'll have an accurate, defensible record instead of a guess.
The Bottom Line
Deductible business miles come down to purpose and position in your day. Your commute to and from your regular workplace is off the table, but the driving you do between business stops — visiting clients, moving between job sites, running work errands — is generally fair game. If you work from a qualifying home office, even more of your driving may count because your day starts the moment you pull out of the driveway on business.
Know the rules, apply the right calculation method, and above all keep a reliable log. The drivers who capture every legitimate mile are simply the ones who wrote them down as they went.