Standard Adding Machine Company

Standard Adding Machine Company was founded in the early 1900s and prospered with the invention of a 10-key adding machine. The machine was a breakthrough for its time because it dramatically modernized computing. Earlier adding machines featured 81 keys, which made them cumbersome and costly and their operators prone to mistakes. The invention won an international grand prize during the 1904 World's Fair and was heralded as a "modern life preserver" in an office journal.

William H. Hopkins, the inventor of the Standard Adding Machine, was a minister. When he moved to St. Louis in 1885 he served as chaplain and then pastor of St. Louis Second Christian Church. He continued to invent during those years and to find better ways to make an adding machine. In the 1890s, he left Second Christian Church and became assistant editor of the company that published "The Christian Evangelist".

Hopkins' success led to competition. By 1915, other adding machine companies were vying for business. In 1916, Hopkins died, and his company began to decline.

Standard Adding Machine closed in 1921. In the decades since, the building housed businesses such as St. Louis Pump & Equipment Co., Lee Paper Co., and most recently, Harrison-Williams Store Fixtures. Vacant since 2003, the building was renovated in 2005 by Aquinas Institute of Theology.

Because of the historical significance of the adding machine, the Standard Adding Machine building is listed on the National Register of Historic Places.