Research the Manufacturer's Suggested Retail Price (MSRP) using the Kelley Blue Book website. Enter your vehicle's make, model and condition to obtain your vehicle's MSRP. Figure your vehicle's age. Check your vehicle registration for your date of purchase if you do not know it.
Visit the Maine Revenue Service page for updated mil rates. Mil rate is the rate used to calculate excise tax. As of August 2014, mil rates are as follows:
YEAR 1 .0240 mil rate YEAR 2 .0175 mil rate YEAR 3 .0135 mil rate YEAR 4 .0100 mil rate YEAR 5 .0065 mil rate YEAR 6 .0040 mil rate
Multiply your vehicle's MSRP by the appropriate mil rate. For example, a four-year-old car with a MSRP of $19,500 would pay an excise tax of $195.00 in Maine.