Greatest mechanical calculating devices of all time

Mechanical calculators are fascinating. They represent the early ingenuity and groundbreaking prowess that paved the way for modern computing. While the iPhone or Android device you are likely reading this on is exponentially more powerful and useful, these devices are where it all began! Mechanical calculators demonstrate the incredible progression of technological innovation and highlight the human drive to solve problems and improve efficiency in mathematical computations.

The Pascaline (1642)

3D illustration of a Mechanical Calculating Device, designed and created by the famous French Mathematician and Inventor Blaise Pascal in the mid XVII Century, named Pascaline in honor of its creator. (Image: J J Osuna Caballero/

Blaise Pascal is renowned for inventing one of the first mechanical calculators: the Pascaline. Capable of performing addition and subtraction directly, this box was designed to assist Pascal's father, a tax collector. Its cogs, wheels, and robust carry mechanism for digit rollovers made it very reliable.

Leibniz Stepped Reckoner (1672)

Image: Hermann Julius Meyer, ed. (1893-1897) Meyers Konversationslexicon, 5th Ed., Bibliographischen Institut, Leipzig, Germany.

Less reliable than Pascal's design, Gottfried Wilhelm Leibniz developed "the Stepped Reckoner." The use of a stepped drum produced a device capable of performing addition, subtraction, multiplication, and division, which was a significant leap in functionality.

Arithmometer (1820)

Image: Ezrdr/Wikipedia

Invented by Charles Xavier Thomas de Colmar, the Arithmometer was the first commercially successful mechanical calculator. It could perform all four basic arithmetic operations and was robust enough for daily office use. This machine remained in production for over 40 years, highlighting its practicality and reliability in an office.

Difference Engine (1837)

London, United Kingdom, June 2018. Babbage's machine is the progenitor of modern computers. It is a mechanical analogic computer, conserved at the London Science Museum. (Image: Massimo Parisi/

Designed by Charles Babbage, the Difference Engine was intended to automate the production of mathematical tables. Although Babbage never completed it due to the technical limitations of his time, the Difference Engine was a marvel of mechanical engineering and laid the groundwork for future developments in computing. In the 1980s, a working version of Babbage's Engine No. 2 was built.

Comptometer (1887)

Image: Ezrdr/Wikipedia

The Comptometer was the first successful key-driven mechanical calculator. Designed by Dorr E. Felt, it allowed for faster calculations through key presses and a crank handle. This innovation made it a staple in offices for decades. Manufactured without interruption from 1887 to the mid-1970s, the Comptometer-style keyboard was a wonder to see used by a proficient operator.

Millionaire Calculator (1893)

Image: Ezrdr/wikipedia

Otto Steiger's Millionaire Calculator was the first mechanical calculator capable of direct multiplication. This machine significantly reduced the time required for complex calculations and was widely used in scientific and engineering applications. It was patented in 1892 and in production until 1935.

Designed by Otto Steiger, a Swiss engineer, the moving carriage of the Millionaire has a 20 decimal digit accumulator that shows the product after multiplication and into which dividend is entered prior to division. The 10-digit multiplicand or divisor is entered on the sliders (or keyboard, on later models) above the carriage, while successive digits of the multiplier or quotient are entered with a push-button lever on the upper left. A large control knob on the upper right can be set to add, multiply, divide or subtract positions.[7]


Curta Calculator (1948)

Curta Type 2 Mechanical Calculator (Image: MarcoPhotoGarcia/

Designed by Curt Herzstark, the Curta was a compact, hand-cranked mechanical calculator capable of performing addition, subtraction, multiplication, and division. Known for its precision and portability, it became highly valued by engineers and rally drivers until electronic calculators took over. The majority of the design work on the Curta calculator was performed by Herzstark while he was captive in the Nazi concentration camp Buchenwald.

Herzstark, the son of a Catholic mother and Jewish father, was taken into custody in 1943 and eventually sent to Buchenwald concentration camp, where he was encouraged to continue his earlier research:

While I was imprisoned inside Buchenwald I had, after a few days, told the [people] in the work production scheduling department of my ideas. The head of the department, Mr. Munich said, 'See, Herzstark, I understand you've been working on a new thing, a small calculating machine. Do you know, I can give you a tip. We will allow you to make and draw everything. If it is really worth something, then we will give it to the Führer as a present after we win the war. Then, surely, you will be made an Aryan.' For me, that was the first time I thought to myself, my God, if you do this, you can extend your life. And then and there I started to draw the CURTA, the way I had imagined it.

— Curt Herzstark, Oral history interview with Curt Herzstark (1987), pp. 36-37[6]

In the camp, Herzstark was able to develop working drawings for a manufacturable device. Buchenwald was liberated by U.S. troops on 11 April 1945, and by November Herzstark had located a factory in Sommertal, near Weimar, whose machinists were skilled enough to produce three working prototypes.[6]


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