When reading a fat free milk label, the number of fat grams you can expect to see is

0 grams of fat should be the answer if is says fat free

zero

Explanation:

If there is fat-free written in a food label than it means the amount of fat in that product is so much less that it will not affect your body fat. FDA allowed any food item which has less than 0.5 grams of trans fat to label it as fat-free.

So if you are reading a fat-free milk label than you should know that you are taking less than 0.5 gm fat per serving and the number of fat grams you can expect to see is zero.