The IRS announced that the standard mileage rate will decrease to 50 cents per business mile driven in 2010. That is a hit of just over 9% from the 55 cents allowed in 2009. According to the IRS, “The new rates for business, medical and moving purposes are slightly lower than last year?s. The mileage rates for 2010 reflect generally lower transportation costs compared to a year ago.”

When you use your car for business, driving between job sites is deductible. So is driving between your home and a temporary job site, job interviews, and conferences. Commuting between your home and a regular place of business generally isn’t tax deductible.

There are two ways for you to calculate your automobile expenses. You can either claim $.55 per business mile driven in 2009 (decreasing to $.50 for 2010), or you can base your deduction on the percentage of miles your car was driven for business multiplied by the actual costs incurred during the year. Allowable costs include gas, insurance, repairs, parking at home, and either your lease payments, or if you own your car, a factor for depreciation.

Generally, unless you drive your car relatively few miles each year, with most of those miles being allowable business miles, you’re better off basing your deduction on the standard mileage rate.

For Example

Let’s say you lease a car for $400 a month that you drive only 3,000 total miles during the year. And of those miles, 2,000 qualify as deductible business miles. By calculating your deduction based on the standard mileage rate, you’ll end up with a deduction of just $1,000 (2,000 business miles * $.50 per mile).

What would your deduction be based on the actual expenses incurred, assuming you spend $1,200 on insurance, $.10 per mile driven for gas, and $1,200 on parking at home? Based on $7,500 of total automobile expenses (including the lease payments), multiplied by two-thirds (2,000 business miles divided by 3,000 total miles), your allowable deduction for your automobile expenses jumps to $5,000 – or five times the $1,000 calculated using the standard mileage rate.

Now let’s see what happens if you drive 20,000 total miles during the year. Assuming your allowable business miles remain at 2,000, you can either claim an automobile deduction of $1,000 based on the standard mileage rate, or $920 based on one-tenth (2,000 business miles divided by 20,000 total miles) of your actual automobile expenses incurred.

Expense 3,000
total miles
total miles
Lease??payments $4,800 $4,800
Insurance $1,200 $1,200
Gas??($.10 per mile driven) $300 $2,000
Parking at home $1,200 $1,200
Total??costs $7,500 $9,200
Business ? use % on 2,000?business miles driven 66.67% 10%
Allowable ? deduction for?auto expenses based
on actual expenses
$5,000 $920

How to Claim The Deduction

Taxpayers who are compensated as employees generally will claim their deductible automobile expenses as an unreimbursed employee business expense. These type expenses are reported on a Form 2106 and are deducted as a miscellaneous itemized deduction on the Schedule A. Keep in mind that miscellaneous itemized deductions are only allowable to the extent they exceed 2% of your income, and are not allowable when calculating the Alternative Minimum Tax (AMT).

Those taxpayers compensated as independent contractors will generally claim their allowable automobile expenses directly against their self-employment income. For these taxpayers, automobile expenses should be reported the Schedule C.

Other Deductible Miles

The use of an automobile in connection with a charitable activity is deductible at a rate of 14 cents per mile for 2009 and 2010 and should be reported with other charitable contributions as an itemized deduction of the Schedule A.

Any mileage driven in connection with a qualified move is deductible at a rate of 16.5 cents per mile in 2010, down from 24 cents per mile in 2010, and should be reported on a Form 3903, Moving Expenses.

And don’t forget that medical related mileage is also deductible. Medical mileage is allowable at 24 cents per mile in 2009, before falling to 16.5 cents per mile in 2010, and should be reported with all other medical expenses on the Schedule A.

Why such a huge decrease for medical and moving mileage rates? According to the IRS, “The standard mileage rate for business is based on an annual study of the fixed and variable costs of operating an automobile. The rate for medical and moving purposes is based on the variable costs as determined by the same study. Independent contractor Runzheimer International conducted the study.”