Skimmed milk and fat-free milk are similar to each other. There is just a difference between names, relating to different brands and different dairies.

Merriam-Webster defines skimmed milk as, 'a milk from which the cream has been removed'. Technically, over 99.5 percent of the fat must be removed, making the product virtually fat-free. Also called skimmed milk, skim milk is the same product as fat-free milk. It stands in contrast to whole cow's milk which retains all of the fat and 1 or 2 percent milk which contains 1 to 2 percent fat, respectively. Skim milk is lower in calories than other milks, while retaining roughly the same amount of most other nutrients.

The only difference is the amount of fat and calories. In fact, skimmed cow's milk contains slightly more calcium than full-fat milk because calcium is found in the watery part, not the creamy part.

Thus, there is no difference between skimmed milk and fat free milk. There is just a difference between names and the names vary according to the brands.