A Brief History of Mechanical Calculators

The purpose of this document is to briefly describe the most common non-electronic calculating devices within an historical context, and to create a source of reference to other pages in the Internet related with this topic. The journey starts 2500 years ago with the Abacus, and ends 30 years ago with the introduction of the first electronic calculators. In order to facilitate the download, the document has been split into three parts: Part I, describes the evolution of the calculating devices up to the invention of the Stepped Wheel by Leibniz. Part II, discusses the main events during the 19th Century, and Part III reviews the development of office machines until the 1960's when the first electronic calculators appeared in the market.