What are FedEx’s commonly used additional surcharge fees?

Fuel Surcharge
A fuel surcharge is one of the most common FedEx surcharges assessed, and It’s assessed to help FedEx offset fluctuating, and often rising, fuel costs. FedEx assess fuel and other surcharges on shipments, without notice. FedEx determines the amount and duration of any such surcharges at their sole discretion.

Non-Machinable Shipment
Non-Machinable Shipment is defined as follows:

1. Any item with one dimension measuring more than 27 inches
2. Any item with any two dimensions each measuring more than 17 inches
3. Any item weighing over 35 lbs. 
4. Any item packaged in a cylindrical shipping tube

Dimensional Weight
Dimensional weight is calculated by multiplying the length by the width by the height of each package in inches and dividing the total by 139. If the dimensional weight exceeds the actual weight, charges may be assessed based on the dimensional weight.

Dimensions of one-half inch or greater are rounded up to the next whole number; dimensions less than one-half inch are rounded down. The final calculation is rounded up to the next whole pound.