What affects shipping cost?

Here is a list of factors and their explanations that affect shipping cost:

DIM Weight: DIM (dimensional) weight refers to the ratio of volume, or the size of your package, to how much the package weighs. The heavier and bigger the package, the more expensive it will be to ship.
Package dimensions: The package dimension refers to the size of the box, pouch, or parcel that your item will be shipped in. This 3-part measurement, length x width x height, informs the shipping company of size of the package or shipment
Delivery speed: Expedited shipping will cost more, sometimes substantially more. It's always good to offer this to your customers along with more economical shipping options. HERE is our iLogistics USA Recommended Shipping services guides. You'll want to evaluate the cost of shipping against how fast your customer wants to receive the package.
Destination: Generally speaking, the further the package is traveling, the higher the shipping cost. This is especially true for international shipping rates. Shipping the same package to California will cost less than shipping to Europe. U.S. shipping rates are based on shipping zones. These are used by companies like UPS, USPS, FedEx and DHL to calculate shipping costs for domestic delivery where each company has their own zone map, so each carrier is different.
Delivery Surcharges: A shipping surcharge is an additional fee added to a shipping cost by the carrier. Shipping surcharges compensate for extra expenses involved in additional handling, special service, unusual delivery, or other expenses inherent in shipping products with exceptional requirements or circumstances.

Fees for especially large or heavy packages
Surcharges for delivering is especially rural areas or areas outside a shipping range
Fuel surcharges