20 CFR 404.204 - Methods of computing primary insurance amounts - general.
(a)General. We compute most workers' primary insurance amounts under one of two major methods. There are, in addition, several special methods of computing primary insurance amounts which we apply to some workers. Your primary insurance amount is the highest of all those computed under the methods for which you are eligible.
(1) If after 1978 you reach age 62, or become disabled or die before age 62, we compute your primary insurance amount under what we call the average-indexed-monthly-earnings method, which is described in §§ 404.210 through 404.212. The earliest of the three dates determines the computation method we use.
(1) Your primary insurance amount, computed under any of the special methods for which you are eligible as described in this paragraph, may be substituted for your primary insurance amount computed under either major method described in paragraph (b) of this section.
(i) The primary insurance amount we compute for you under the average-indexed-monthly-earnings method;
(iii) The primary insurance amount computed under what we call the old-start method; as described in §§ 404.240 through 404.242.
(5) In some situations, we use what we call a special minimum computation, described in §§ 404.260 through 404.261, to find your primary insurance amount. Computations under this method reflect long-term, low-wage attachment to covered work.