The Curta Calculator

by Jenny Mitchell

The Curta Calculator is an amazing instrument. Unlike the calculators we use today, it contains no electric or electronic parts, and is in fact powered by a small hand crank.
The Curta Calculator was designed by an Austrian man named Curt Herztark around 1945. Astonishingly, Herztark developed the calculator while imprisoned in a German concentration camp, called Buchenwald. Apparently, the camp leaders were aware of his work, and even encouraged it! It is thought to be true that Herztark was given a drawing board, and he worked on his design day and night. In 1945, his work payed off when the camp was liberated and Herztark took his plans with him. The Curta I was first manufactured in 1948, and was quickly followed by the Curta II in 1954, a larger model with 15 digit results rather than the Curta I’s 11. Each calculator was sold with a metal case. The product was manufactured until the early 1970’s when digital calculators became widely used.
The Curta is incredibly dissimilar to calculators students use today. Small, and cylindrical, it could almost be mistaken for a pepper grinder! It has slides on its side, and a “result counter” and “revolution counter” on the top of the machine. The defining aspect of the calculator is that it has absolutely no electric or electronic parts. It is much quieter than its ancestors, as well as being much smaller. All this means that the Curta calculator is much more accessible than earlier calculators.
The Curta Calculator can be used to perform many kinds of operations, ranging from multiplication to division and from square roots to algorithms. For example, to add, turn the crank once. The input number will then be added to the result counter. If you would like to perform a subtraction operation, simply pull the crank out slightly before turning it.

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