5 Mileage Tracking Mistakes That Cost You Money at Tax Time
Are you undercounting your business trips? From rounding numbers to forgetting odometer readings, these common errors could be slashing your tax refund. Learn how to fix them.
Tracking your business mileage is one of the easiest ways to lower your tax bill. Every trip you take to a client, a job site, or a supply store is money back in your pocket.
However, many leave thousands of dollars on the table—or worse, put themselves at risk of an audit—because of a few common mistakes.
Here are five mileage tracking errors that could be costing you money right now, and how to fix them before tax season arrives.
Mistake 1: Not Tracking Short Trips
It's easy to remember a 50-mile trip. It's much harder to remember a 2-mile trip to the post office or the bank.
Why it costs you: Short trips add up. If you make just three "quick" business errands a week, that’s over 300 miles (480 km) a year. At 2026 rates, that’s hundreds of dollars in lost deductions.
The Fix: Use a tracking system that captures every drive automatically. When you don't have to think about it, those short trips become "found money."
Mistake 2: Counting Your Commute as Business Mileage
This is the most common reason mileage deductions are denied. Commuting is the drive from your home to your regular place of work. No matter how far it is, it's a personal expense.
Why it costs you: If an auditor sees that you've included your daily commute, they may throw out your entire deduction.
The Fix: Learn the rules. Generally, business travel only begins once you arrive at your first work location or if you work from a qualifying home office.
Mistake 3: Rounding or Estimating
If your log shows nothing but 10 miles, 20 miles, and 50 miles, you are asking for an audit.
Why it costs you: Real-world trips almost always have decimals. When an auditor sees only round numbers, they know you're guessing, which is grounds for disqualifying the log.
The Fix: Record exact mileage, including decimals. GPS-based trackers like automileage.app do this for you.
Mistake 4: Tracking Miles but Forgetting the Purpose
A log showing "12.4 miles" is only half-complete. Without a recorded business purpose, it's just a number.
Why it costs you: To claim a deduction, you must prove the trip had a legitimate business connection. If you're audited, you'll need those details.
The Fix: Get into the habit of adding a quick note to every trip as soon as it ends.
Mistake 5: Forgetting to Log Odometer Readings
Your business deduction is based on your "business-use percentage"—business miles divided by total miles driven in the year.
Why it costs you: To calculate that percentage, you must know your odometer reading on January 1st and December 31st.
The Fix: Take a photo of your dashboard on January 1st and December 31st. automileage.app will prompt you for these readings to ensure your records are complete.
Conclusion
The days of handwritten notebooks on the dashboard are over. Digital tools like automileage.app eliminate all five of these mistakes automatically.
Stop losing money on your mileage—start tracking with automileage.app today.