Calculators were the earliest form of moving mechanical aids to calculation. Pioneered by Wilhelm Schickard and Blaise Pascal in the early 1600s, and improved by Gottfried Wilhelm Leibniz in the later 1600s, mass production had to await the industrial revolution before production facilities could reliably produce the complex interchangeable parts that most of them required.
The first commercially available machines were produced (to the Leibniz design) in the mid-1800s by Charles Xavier Thomas de Colmar and there was a thriving industry by the early 20th century. Most mechanical calculator manufacturers transitioned into the production of electronic machines in the 1960s. Some even attempted to produce small computers, but were usually driven out of business by larger firms.