Fuel mileage is easily calculated. Most of you probably know how to do this calculation so just humor me. Fuel mileage can be figured over any given time span. I prefer to have a year of data before I calculate fuel mileage because of weather changes during the year. The issue applies, the more data you have the more accurate your figures will be. You must fill your tank at the beginning and ending mileage figures. Partially filling your tank will not give you accurate calculations. I prefer to let the mechanical kick off at the pumps shut off when filling the tanks. The reason for this is that if you keep filling your tanks to an even dollar figure your mileage will be distorted, thus making your records not as accurate as they should be and you want to be as accurate as possible. When you consider the volume of fuel utilized, accuracy is critical. To figure out fuel mileage do your initial fill up and record your mileage, keep track of your gallons of fuel after your initial fill up and your cost of purchases over a mileage span. Then when you decide to fill your tanks, add up all your gallons and cost of purchases for that time. Then subtract your beginning mileage when you filled your tanks from the mileage of the last time. Divide your miles by gallons used. This gives you your mpg (miles per gallon). Take your mpg and divide into your total cost giving you an average cost per gallon. Again, I repeat it is very important to fill your tanks on the initial fill up and the final fill up. Here is the formula for calculating fuel mileage:
ENDING MILEAGE - BEGINNING MILEAGE --MILES TRAVELED + GALLONS USED = MILES PER GALLON
This is the formula for calculating average cost per gallon.
TOTAL COST + GALLONS PURCHASED = AVERAGE PRICE PER GALLON.
This is the formula for calculating your cost per mile for fuel expenses.
AVERAGE PRICE PER GALLON + MILES PER GALLON = COST PER MILE
