The fuel surcharge percentage for FedEx Freight® services is based on the weekly published national U.S. on-highway average price for a gallon of diesel fuel. FedEx GroundFuel Surcharge Rates Effective DateFedEx GroundSurchargeBased on Weekly Fuel Price Reported for*May. 31, 2021-June. 6, 20218.00%May 24, 2021May. 24, 2021-May. 30, 20218.00%May 17, 2021 *There is a lag between the fuel price index and.