The Curta Calculator

Having the ability to add, subtract, divide, and multiply at the tip of our fingers is something that is taken for granted today. However, there was a time when a basic four-function calculator spanned an entire desktop, and the only means of portable calculation was a slide rule (which, as it sounds, is a device containing three or more ruler-like scales which slide along each other to perform division, multiplication, and so on). It was during this time that the Curta Calculator arrived on the market. Being the first pocket calculator is noteworthy in and of itself, but what makes the Curta truly unique is that it is a mechanical calculator—that means no batteries, no circuitry, and no electronics. Although that may seem peculiar today, mechanical machinery was the norm for centuries. By the time of the Curta, people had explored all manner of mechanics to create clocks, music boxes, typewriters, calculators, and much more. In fact, mechanical calculators can be traced all the way back to the seventeenth century with devices like Pascal’s Pascaline and Leibniz’s Stepped Reckoner. During the interim, the goal to manufacture more powerful and more portable calculators was self-apparent; yet, it would take over two centuries to create a calculator of the Curta’s small size and impressive functionality—a testament to the achievement that is the Curta Calculator.

Alongside the unique circumstances surrounding its conception, the Curta is distinctive in form and function. It’s most striking feature is the large crank on top of its black cylindrical body. That, in combination with its small size, has earned the Curta many comparisons to a coffee grinder. Despite being rather compact, the Curta is a fully featured calculator, more so than many desktop-sized mechanical calculators of its time. It can add, subtract, multiply, divide, perform root extractions, and more with the right know-how. For the basics, it only takes a bit of observation and practice. A set of sliding knobs surrounding the cylinder allows for numbers to be inputted; manipulating the crank will determine the operation performed with said number. Additionally, the top of the cylinder can be rotated to change how many times the operation is performed (by powers of ten). On top of the cylinder is a counter which displays the number of operations performed (turns of the crank). Additionally, the results are also displayed on top, up to eleven digits. With eleven digits, the Curta has a higher level of precision than many modern pocket calculators. Additionally, it is capable of dealing with decimals and percentages. That verbal description may sound cumbersome but with practice, it could be quite agile. For example, it was the preferred calculator for rally car drivers and other professionals for decades. To proceed with a description of the internal mechanisms of the Curta would require a lengthy discussion of the many intricate interactions present between the 600+ parts. The complexity of the Curta was not the only thing which made it difficult to produce; the Curta’s creator Curt Herzstark faced great adversity in his life, and it is astonishing that he was able to ever bring the Curta to market.

Curt Herzstark was born July 26, 1902, in Vienna, Austria, to Samuel and Marie Herzstark. Samuel decided to establish the Austrian Calculating Machines Manufacturing Company in 1905 with the monetary assistance of a banker named Gustav Perger. He studied the calculators of the day and sought to improve them, with the majority of his early work being based on Charles Xavier Thomas’ arithmometer. It took little time for the business to become successful enough to pay off the debt with interest. However, the onset of the First World War came soon thereafter, and Austria’s economy would suffer significantly because of it. In turn, the company was forced to switch to manufacturing for the war effort in order to survive. During this time, Curt went through high school and then college, all in preparation so that Curt could successfully take his father’s place as the owner of the factory. After college, Curt performed a variety of duties in the factory, from sales to engineering. Samuel even had Curt work outside his factory to ensure that he would become a well-rounded engineer and businessman. In 1926, competitors were creating big machines, which were ever more expensive and electric, but Curt noticed that the market was missing something—a portable calculator. It was then that he began working on his magnum opus. By 1937, he had almost completed his plans for the Curta, but there would be a major delay in finishing the device—the Second World War. German officers demanded that every technical factory be repurposed for use in the war effort. This living arrangement, though tough, would permit Curt some safety and stability during this time. However, the higher-ups would come after him in 1943 because of the presence of English radios in the factory. Curt, being ethnically half-Jewish, was sent to a concentration camp called Buchenwald, while the other workers in the factory were sent to prison or even killed on the spot. Curt’s position as a technician secured him some protection in the camp because the officers there thought that the Curta would make a great birthday present for Der Führer, Adolf Hitler. Fortunately, Curt did not have to wait and see if his invention would please Der Führer, as U.S. troops rescued him in 1945. By this time, Curt’s plans for the Curta were fully fleshed out, and all he needed was the funds for it. At first, he searched in Weimar, but the danger of being deported to the Soviet Union to become an involuntary industrial engineer was too high. Curt decided his only option was to go on a long and arduous journey back to his family factory in Vienna. Upon arriving in Vienna, Curt was met by some agents that the country of Liechtenstein had sent out in search of engineering talent. Curt was brought to the Liechtenstein Palace in Vienna to be informed that the Prince approved of his invention and wanted to fund its production. Curt happily accepted and by 1948, despite all the difficulties, the Curta was finally manufactured and shipped for sale. It was internationally successful and would be the final device that Curt would work on before retiring.

In 1961, the first all-electronic desktop calculator arrived on the market; a decade later the first truly “pocket” electronic calculators arrived, and they were more portable and economical than the Curta. By 1972, the Curta ceased production—its time in the spotlight was over. Now, the Curta is a relic from a bygone era where mechanics were the uncontested king, driving everything small and large. However, the Curta did not end up as rubbish like many of the calculators which preceded and followed it. In fact, collectors value the Curta more highly than its initial asking price, even when adjusting for inflation. The ingenuity and workmanship that Curt Herzstark placed in his calculator have imbued it with intrinsic value beyond its functional utility. It is much like fine mechanical watches that are valued highly for their beauty and time-honored craftsmanship, despite not being able to compete with the price and precision of quartz watches—another affirmation of the notion that hard work will ultimately be recognized and appreciated by others.