The fuel surcharge percentage refers to the markup that trucking companies place on invoices to cover the cover fuel costs for the delivery. The exact percentage used to determine the surcharge typically changes based on the current costs of diesel fuel at the time of the delivery, the base rate per mile you charge for fuel and your average miles per gallon. The calculation, however, remains the same regardless of current fuel prices.
Figuring Fuel Surcharge Percentage

To figure the fuel surcharge percentage, you must calculate the average cost per gallon. Add up the total fuel costs for the trip and divide that by the total gallons bought. For example, if you pay $3,890 for 1,000 gallons of diesel, you get an average per gallon cost of $3.89. Alternatively, you can use the U.S. Energy Information Administration’s weekly average diesel price. You subtract the baserate from the average per gallon. If you charge a base rate of $1.50 per gallon, you get $2.30. You divide $2.30 into your average mileage. At a standard 6 miles per gallon, you get $0.383. Divide that number into your base rate and, in this example, you get 0.255, or 25.5 percent. Multiply this percentage by total, pretax cost of the delivery. A $1,300 delivery at 25.5 percent receives a $331.50 fuel surcharge, for a $1,631.50 pretax total.
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