Some tips for keeping a vehicle mileage log are to always note down the odometer readings, the destination and the purpose of the business trip in written or electronic format and to gather relevant documentation as proof for mileage deduction. Also, consider installing global positioning software in the vehicle.
A vehicle mileage log can be maintained in the written form in a notebook or a mileage log form. These books and forms are available for purchase from local office supply shops or as downloads from the Internet. Keep either of these in the car at all times.
To ensure that the log is accurately filled out, record the beginning and ending readings of the odometer every time a business-related trip is undertaken. Write a detailed purpose and gather evidence to prove the distance traveled so that this information would satisfy an IRS auditor. Some evidence that can be collected includes maps and driving direction print-outs.
Also, know the business trips that qualify for mileage deductions, such as travel between two business places, conference trips, visits to customers and travel to airports.
If the log is maintained in an electronic format, use applications such as MileIQ to enter the relevant details. Such applications calculate mileage and enter it into a document that is tax compliant or export it into a spreadsheet.
A global positioning system installed in the car also helps track business mileage. However, create backups of such data as the software may experience glitches or the hardware may crash.