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  Surveying Instrument Collection 


Cortina Ltd, Mauren, Liechtenstein


Curta Model II, System Curt Herzstark

Serial Number



65 mm diameter, 110 mm high




Black-and-white photos from Siegrist, W. 1992. Die CURTA Rechenmaschine - Eine Legende. Vermessung, Photogrammetrie, Kulturtchnik (VPK), Vol. 90, No. 3, pp. 138-142.


This mechanical handheld calculator has 11 adjustable digits on the sides of the cylinder and 8 and 15 display digits on top. The calculator can be used for addition, subtraction, multiplication and division. Before the introduction of electronic calculators (e.g. Hewlett-Packard HP 35 in 1973), the CURTA was used by many surveyors in field and office, often in conjunction with trigonometric tables.

When multiplying, the larger factor is set on the sliders on the side and the smaller factor is applied from the right most digit by turning the operating handle at the top. 1 rotation = multiplication by 1.

The top ring can be lifted to do the multiplication with the second digits from the right and so forth. The second factor is confirmed on the 8 digit register (metallic colour) on top. The result of the multiplication is shown on the 15 digit register (black colour) on top.

The two top registers can be cleared between computations with the clearing lever. The operating handle can be lifted to apply subtractive turns.

For further details of the operation of the CURTA, please consult the internet (e.g. www.vcalc.net/cu-man2.htm).

History & comments

The inventor of the CURTA, Curt Herzstark, was born on 26 January 1902 in Vienna. His father owned a factory for mechanical calculating machines (Rechenmaschinenfabrik Austria, Herzstark & Co.). Curt did an apprenticeship as a fine mechanic. The possibility of a hand-held calculator was first discussed in 1928. Because of a Jewish grandmother, he was transported to the Concentration Camp Buchenwald during the second world war. However, he was allowed to continue to work on the design of such a hand-held calculator. After the war, some parts of a first prototype were manufactured in East Germany. C. Herzstark then fled to Vienna, where the manufacturing prospects were not much better.

A first offer for commercialisation came from a manufacturer of calculating machines in Zurich (Prezisa AG). A better offer followed from the ruling house of Liechtenstein, where production eventually started in 1948. The firm Contina Ltd manufactured a small CURTA (Model I with 8x6x11 digits) and a large CURTA (Model II with 11x8x15 digits). Over the years, 80'000 Model I and 60'000 Model II machines were produced.

The introduction of electronic calculators (e.g. the Hewlett-Packard HP 35 in 1973) brought the production of CURTA to an end. Curt Herzstark died on 27 October 1988 in Liechtenstein.

Further information on the history of the CURTA can be found, for example, in Siegrist, W. 1992. "Die CURTA Rechenmaschine - Eine Legende". Vermessung, Photogrammetrie, Kulturtchnik (VPK), Vol. 90, No. 3, pp. 138-142.


in metal container, 72 mm diameter, 130 mm high


excellent, some paint damage on container


The instrument and was donated by Bill Rein, Surveyor, Balgowlah NSW in April 2012.


Catalogued by JMR on 15 June 2015. Photo by JMR.

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