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Curta Calculators ~ Vintage Mechanical Calculators

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1950 Curta Mechanical Calculator

Curta Calculators

Vintage Curta Calculators are small hand held mechanical calculators with a hand crank introduced in the late 1940s. The Curta calculator was considered the most accurate portable calculator available, and was widely used by scientists, engineers, surveyors, and accountants during the 1950s and 1960s until they were displaced by electronic calculators in the 1970s.

The Curta is a type of mechanical calculator known as a stepped drum calculator. This small cylinder calculator looked almost like a pepper grinder or peppermill. The first productions of the Curta calculator were initially shown at the Basel Trade Fair in Switzerland in May of 1949.

The Curta calculator was invented by Curt Herzstark, an Austrian inventor and manufacturer of calculators, who completed the design of this mechanical calculator while imprisoned in the Buchenwald concentration camp in Germany during WWII. The entire story of this is recounted in an interview with Curt Herzstark that is available in pdf format here: Curt Herzstark Interview (1987)

To use the Curta calculator one would hold the mechanical calculator in the palm of your left hand, while using the hand crank with your right hand. There were two versions of the Curta calculator, the Type I and the Type II.

According to a reproduction of a CURTA brochure, the differences in the two models of the calculator are their calculating capacities and weight.

The brochure lists the two types as follows:

CURTA Model I, calculating capacity 8x6x11 digits (weight 8 ozs.)

CUTRA Model II, calculating capacity 11x8x15 digits (weight 12 ozs.)

With the invention of the electronic calculator, mechanical calculators like the Curta became obsolete, and production of the Curta calculator ceased in 1972. As with many unique but outdated inventions, the Curta Calculator has become a collectible item. You can buy a vintage Curta Calculator on eBay. I've listed some of the recent sale prices and values of Curta calculators towards the bottom of this page.

More about the Curta Calculator:

Curta Calculator Serial Numbers and Dates Produced

Curta Calculator Art Print Poster

Do You Own a Curta Calculator?

Curta Calculators

Curta Calculators

The Astounding Curta Mechanical Calculator - How the Curta Calculator Works

Witness the jaw-dropping ingenuity of this fascinating hand-held mechanical calculating machine. Watch this video below to see how the Curta calculator can do addition, subtraction, multiplication, division, and even more. This video show a variety of mathematical calculations. He even takes the cover off his mechanical calculator showing you the internal mechanisms of the calculator.

1969 Curta Mechanical Calculator Print Ad

1969 Curta Mechanical Calculator Print Ad

1969 Curta Calculator Print Ad

Curta Calculator Advertisement

This 1969 Curta Calculator magainze print advertisement reads:


All Purpose Calculator

(Curta Calculator picture)

Scroll to Continue

Weighs only 8 oz.


Curta adds, subtracts, multiplies, divides, square and cube roots, continuous multiplication, negative multiplication, standard deviations and all statistical calculations, squares and higher powers, co-ordinates and associated land survey formulae, and every other computation arising in science and commerce....Available on a trial basis.

Price $125.00. Write for literature.

Curta Company

Dept. SA-9 P.O. Box 3414

Van Nuys, California

Curta Mechanical Calculator

Curta Mechanical Calculator

Curta Mechanical Calculator

Curta Mechanical Calculator photo by Jeff Keyzer

The placard behind this museum displayed

Curta Calculator reads:


The Curta mechanical calculator provided more accurate results than a slide rule. Numbers were entered in the "coffee grinder" by moving the small knobs on the side, the crank was turned, and the result was displayed in the silver area on top.

About Curta Calculators

About Curta Calculators

Curta Calculator History photo by Marshall Astor

Another museum placard reads:

Curta Calculator, 1948-1970, Mauren Contina Ltd., Liechtenstein

Austrian Curt Herzstark designed a calculator while imprisoned in a Nazi concentration camp during WW II. Soon after the war, Herzstark established a factory in Liechtenstein that manufactured the calculators from 1948 until the early 1970s. The devide, a very small and highly sophisticated calculating machine, was based on Leibniz's stepped drum concept. The small Model I had eleven digits of accuracy, while the Model II had fifteen. Herzstark called his invention "Curta", a name he had wanted to give the daughter he never had.

What is the Value of Curta Calculators

Many people who own a Curta Calculator are interested to know what it's worth. One way to find out the estimated value of a Curta Calculator is to see what other calculators in similar condition have recently sold for. You can do this by browsing the SOLD listings on eBay.

This is a small sampling of Curta calculators that have SOLD on eBay recently. I update this page occasionally with the newest sale prices from ebay. This can give you a good indication of the Value of Curta Calculators. As with any collectible item, values are affecting by rarity, condition of the item, and the number of bidders on any one particular auction. The most valuable and rarest of the Curta calculators are the Demo calculator kits.

Curta Calculator Value

  • Curta Calculator Type 1 Demo Kit - Contina A.G. Vaduz/Liechenstein - Sold for GBP 6,210.00 ~ US $ 9,716.79 (Sold on Oct 1, 2011)
  • Curta Calculator Demo Kits are rare to find. This one was in excellent used condition with all components present and the mechanism was fully operational. The serial number was 35177.
  • VERY EARLY CURTA Calculator Type 2 #500236 in near MINT Condition! - SOLD for $3400
  • Rare Early 1949 Curta Calculator Type I, Low Serial Number 4468 in good condition - Value / Worth - Sold on eBay for GBP 1.995 ~ US $3,121.58
  • RARE - Early CURTA Calculator TYPE I #9241 - MINT STATE - 1950 - SOLD for $2499
  • Early CURTA Calculator TYPE II #507757 - MINT STATE - 1956 - SOLD for $1999.00
  • SALE ! RARE ! EARLY CURTA Calculator Type 1 #4950 with PIN SLIDERS ! near MINT ! - SOLD for $1890.00
  • Curta Type II Calculator with original manuals and vintage leather carrying case. Serial # 544804 - SOLD for $1825.00
  • CURTA Calculator Type I, Serial Number #6397 - Value / Worth - Sold on eBay for GBP 1,108.50 ~ US $1,734.47
  • Rare Early CURTA Calculator TYPE II #508697 in Mint Condition - Value / Worth - Sold on eBay for $1,599
  • Antique CURTA Calculator Type I Serial #78000 in Mint Condition - Value / Worth - Sold on eBay for $1500
  • EARLY CURTA Calculator Type 2 in MINT condition, Low Serial # 503651 - Value / Worth - Sold on eBay for $1,499
  • EARLY CURTA Calculator Type 2 #508619 in MINT Condition - Value / Worth - Sold on eBay for $1,499
  • June 1968 Late CURTA Calculator TYPE II #559546 - Like New Condition, WITH BOX - Value Worth - Sold on eBay for $1,399
  • CURTA Calculator Type 1, Excellent, serial number 13517, Made in 1951 - Value Worth - Sold on eBay for $1320
  • CURTA TYPE II CALCULATOR in NEW State with original case and manuals, appears to have been never used, Serial number 559962 which places it's manufacturing date around November 1970 - Value / Worth - Sold for GBP 850 ~ US $1318.78
  • Late CURTA Calculator Type II, Serial Number #549450 - January 1966, Like New State - Value Worth - Sold on eBay for $1299
  • RARE : EARLY CURTA Calculator Type I #25811 in MINT Condition! LOW serial number, fully serviced the 9th of July - Value Worth - Sold on eBay for $1205
  • Curta Type I 1 Vintage Hand Crank Mechanical Calculator, No. 70141, May 1968, manual in both German and English included, tube case included - Value Worth - Sold on eBay for $1200
  • Early CURTA Calculator TYPE I #15604 Very Good State - Serial Number 15604, September 1951 - Value Worth - Sold on eBay for $1199
  • Early CURTA Calculator Type 2, Low Serial Number #507285 in MINT Condition - Value Worth - Sold on eBay for $1184.99

Photos of CURTA Calculators - These Curta Calculators are NOT for Sale

Curta Calculator

Curta Calculator

Curta Calculator photo by Dan Zen

Curta Calculator Type I

Curta Calculator Type I

Curta Calculator Type I photo by Food Fetishist

The info reads Curta Calculator - Type I, Liechtenstein, c. 1947-1970

Curta Calculator Type II

Curta Calculator Type II

Curta Calculator Type II photo by Food Fetishist

This photo is obviously taken in a museum. The information in front of the calculator reads: "Curta Calculator - Type II, Liechtenstein, c. 1954-1970.

Curta Calculator in Action

Curta Calculator in Action

Curta Calculator photo by RobotSkirts

Curta Calculator

Curta Calculator

Curta Mechanical Calculator photo by Jon Callas

Curta hand calculator, Deutsches Museum, Munich

Curta Calculator - Curta Calculator invented in a WWII Concentration Camp

Assembly of YACS - Yet Another Curta Simulator - How to Assemble a Curta Calculator

This is a simulation video using virtual reality modeling language to show the parts and assembly of a

Curta Calculator.

How the Curta Calculator Works - Curta Calculator Simulator

Comments and Questions about the CURTA Calculator - How did you like this Curta Calculator Page?

ephemerania lm on March 27, 2012:

Fascinating...I've seen many different types of calculating devices but was not aware of these !

klaird on November 26, 2011:

The simulation videos of how the Curta calculator works are interesting to watch.

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