How to Create a Mileage Log: Your Complete Guide

Why Your Mileage Log Matters So Much

Creating a mileage log that satisfies the IRS or your employer ensures you unlock valuable tax deductions and receive proper reimbursement. For tax purposes, failing to keep a detailed, accurate log is one of the most common reasons mileage deductions get denied during an audit. Don’t let missed paperwork cost you thousands!

Keeping a solid mileage log isn’t just about ticking a box; it’s about protecting your finances.

• Tax Savings: Every single business mile driven is potentially worth a deduction. The IRS allows you to deduct a set amount per mile (the standard mileage rate, which changes annually). Missing documented miles means missing out on significant tax savings that can easily add up to thousands of dollars per year. 
• IRS Compliance: The IRS requires specific documentation to back up your business mileage deduction. If you’re audited and can’t provide a sufficient log, your deduction will likely be disallowed. An organized log prepares you for any questions the IRS might have.
• Accurate Reimbursement: If you drive for work but aren’t self-employed, your employer needs an accurate log to reimburse you correctly. Avoid disputes and ensure you get paid for every business mile.

What the IRS Requires: The Non-Negotiables for Your Mileage Log

To be IRS-compliant, your mileage log must include certain key pieces of information for each business trip. Think of this as the essential data list. If your log is missing any points for a trip, that trip might not be deductible.

Here’s what the IRS mandates you record:

• Date: When the trip occurred.
• Starting Location: The address or specific place where your business trip began.
• Destination: The address or specific place where your business trip ended. Providing enough detail helps verify the route and purpose.
• Total Miles Driven: Calculated based on the beginning and ending odometer readings for that specific trip. The IRS wants actual mileage based on your odometer, not estimations. Summing up weekly or monthly miles without per-trip detail isn’t sufficient.
• Purpose of the Trip: A clear explanation of why the trip was business-related. Examples include “Client Meeting,” “Supply Run,” “Site Visit,” “Delivery to [Client Name],” “Meeting with Accountant.”
• Starting and ending odometer reading of the year: You are not required to include your odometer readings after each trip, but your odometer reading has to reflect how much you drove during the tax year.

These recordkeeping requirements are consistent across the U.S. for federal taxes, though some states might have extra rules.

Here is a quick video guide to help you navigate mileage log requirements: ▶️

How To Create a Mileage Log After the Fact

Creating a mileage log is pretty straightforward if you have recorded every needed detail. You upload them in a spreadsheet or a mileage log software, and there you go.

But don’t worry, if you are unsure you recorded everything correctly, missed some trips, or didn’t record altogether,  you can still create a compliant log. This requires some detective work and the right tools. Standard mileage tracking apps are designed for future trips; they don’t help much with the past. The focus shifts to gathering clues and using tools that help piece together history.

Here’s how you tackle creating a mileage log for trips that already happened:

Gather Every Piece of Evidence

Your mission is to find anything that proves you were at a specific business location on a specific date. Look for:

• Your calendar (meetings, appointments)
• Emails (meeting confirmations, client communications, order receipts with dates/times)
• Expense reports or receipts (parking, tolls, gas bought near a client location)
• Phone records (call logs to/from clients)
• Location history data from your phone (if you had it enabled – this is a goldmine!)
• Client invoices or work logs
• Physical appointment books or diaries

Choose Your Creation Tool

You need a system to build the log based on your evidence.

• Spreadsheet (Excel or Google Sheets): You can download free IRS-compliant mileage log templates online. These give you the columns needed (Date, Start Location, End Location, Odometer Begin/End, Miles, Purpose). You’ll manually enter data based on your evidence. This is affordable but can be incredibly time-consuming and prone to errors when reconstructing.
• Use a Specialized Software: Some tools are specifically designed to help you reconstruct past mileage using the evidence you gathered. These often offer features like importing historical data and applying IRS rules.

Reconstruct Each Trip

This is the core work. For each business appointment, visit, or errand you identify from your evidence:

• Note the date.
• Determine the starting point (usually home or office, or the previous business stop).
• Identify the destination (the client, supplier, post office, etc.).
• Enter your miles for the trips. A mapping tool (like Google Maps or another service) can find the likely route and distance between your start and end points for that date.
• Clearly state the business purpose.

Calculate Total Miles

When you file for a deduction, you will need to enter your total business miles. Ensure your total miles match your odometer reading at the end of the tax year. If you use your car for personal trips as well, you will have to take those into consideration too.

Review and Refine

Before calling it quits, go through your reconstructed log. Does it make sense? Are there any gaps? Does every trip have all the required IRS details? Look for inconsistencies. This review process helps catch errors that could cause issues.

Organize and Store Securely 

If you use spreadsheets, save multiple copies and back them up to cloud storage. If using software, ensure it provides secure storage and easy access to reports. You need to keep these records for a minimum of three years after you file your tax return.

Creating logs this way manually can be a massive undertaking, especially for a full year of driving. It requires discipline and careful attention to detail to ensure compliance without guesswork.