Familiar with the machines of Pascal and Moreland, Leibniz envisioned a calculator that could perform the four arithmetic functions with speed and accuracy. He saw their value in business and government, but his primary interest was science.

His machines, which he called his living bank clerks, had two basic elements: a collection of pin wheels for adding, similar to Pascal's, and a movable carriage that could follow decimal places when multiplying. The two sections were linked by stepped cylinders containing ridge-like teeth of different lengths corresponding to the digits 1 through 9. Turning the crank that connected the cylinders engaged the smaller gears above the cylinders, and these in turn engaged the adding section.

Much to Leibniz's disappointment, his machines did not meet his intended excellence. In fact, they were cumbersome to operate and inaccurate.

It has been said that if Leibniz had lived longer, he would probably have conceived the idea of a programmed computer. That is pure supposition. But his invention was a crucial step forward in the visionary phase of development.