In the US, typically used range from five letter designations: «A», «B», «C», «D» and «F». «A» - the highest rating, «F» (from the English. Failure) - the lower, meaning unsatisfactory result. These symbols correspond to the first letters of the Latin alphabet in alphabetical order of the same, except for the letter «E».

Widely used versions extension scale by + and - signs are commonly used. They are usually considered as x + 0,3, respectively, and x-0,3. For example, since B = 3,0, then B + = 3,3 and B- = 2,7. Some educational institutions use a single mid- point between the units of the scale. They consider evaluation A- and B + identical. In such cases, the evaluation of AB replaces the option A- / B + and is counted as 3.5

Evaluation of A + - innovation in American education. A smaller part of the institutions that use it, evaluate it as 4.3 or 4.5, but many estimate of A + as 4.0, because they believe that the 4.0 scale can not go higher than 4.0. Sometimes falls F-, believing that everything below D, by definition fail. Estimated percentage A 90% -100% B 80% -89% C 70% -79% D 65% -69% F and below 64%