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Curta Dating

(since April 22, 1997)

Last Update: October 04, 2021 -- THE CURTA REFERENCE

NEW!     CURTA I SERIAL NUMBER ANALYSIS by Hansjorg Nipp - June 2021

CURTA 1 Date by serial number

 CURTA I Serial Number Analysis
The development of Curta I production quantities in the first few years.pdf
Year Serial number pieces produced
19470
1948900 - 999100 max
19491900 - about 2200300
1950about 2200 - about 69004,700
1951about 6900 - about 12,6005,700
1952about 12,601 - about 20,7008,100
1953about 20,701 - about 24,4003,800
195424,401 - 28,200 3,800
195528,201 - 32,000 3,800
195632,001 - 35,800 3,800
195735,801 - 38,860 3,060
195838,861 - 40,770 1,910
195940,771 - 41,770 1,000
196041,771 - 45,010 3,240
196145,011 - 49,170 4,160
196249,171 - 52,880 3,710
196352,881 - 56,130 3,250
196456,131 - 58,580 2,450
196558,581 - 62,180 3,600
196662,181 - 65,780 3,600
196765,781 - 68,780 3,000
196868,781 - 73,580 4,800
196973,581 - 77,780 4,200
197077,781 - 80,4272,647
total productionabout 78,727

Curta II serial numbers

Here are some notes from Hansjoerg about the Type II serial numbers:
There is no really good information available about the [type II] figures.
There are only the until now known figures from a curta service,
but there are no documents from the company itself.
I have only some rare information about the serial numbers form 1952 and the first half of 1953.
I got this information from the private archive from Curt Herzstark (I have access to that archive).
From these dates I did an estimation:
1952 quantity about 500 pieces , serial number 500'000 to 500'500
1953 quantity about 2000 pieces, serial number 500'501 to 502'500
1954 quantity about 1500 pieces, serial number 502'501 to 504'00
1955 quantity about 2500 pieces, serial number 504'001 to 506'500,
I found an invoice from November 1955 with serial number 504'052
My guess for the next years (without having strong proofs):
1956 quantity about 2520 pieces, serial number 506'501 to 510'020
numbers from 1957 to 1970 according the list already known

New for me was that type II's were sold in 1952 and early in 1953.

FACTORY PRODUCTION LISTS     (Oct 03, 2011)

These lists were produced by a former Curta Factory worker. Thanks to Hans for providing them.

CURTA I
Year      Serial number         pieces produced
1947 901 - 3,0002,100
1948 3,001 - 6,000 3,000
1949 6,001 - 9,200 3,200
1950 9,201 - 12,6003,400
195112,601 - 16,6004,000
195216,601 - 20,6004,000 CURTA II
195320,601 - 24,4003,800 YearSerial number              pieces produced
195424,401 - 28,2003,800 1953/54500,001 - 505,1205,120
195528,201 - 32,0003,800 1955505,121 - 507,1202,000
195632,001 - 35,8003,800 1956507,121 - 510,0202,900
195735,801 - 38,8603,060 1957510,021 - 510,520500
195838,861 - 40,7701,910 1958510,521 - 511,5201,000
195940,771 - 41,7701,000 1959511,521 - 513,5202,000
196041,771 - 45,0103,240 1960513,521 - 516,5203,000
196145,011 - 49,1704,160 1961516,521 - 519,0202,500
196249,171 - 52,8803,710 1962519,021 - 522,5203,500
196352,881 - 56,1303,250 1963522,521 - 526,1203,600
196456,131 - 58,5802,450 1964526,121 - 530,3204,200
196558,581 - 62,1803,600 1965530,321 - 533,9203,600
196662,181 - 65,7803,600 1966533,921 - 539,3205,400
196765,781 - 68,7803,000 1967539,320 - 544,7205,400
196868,781 - 73,5804,800 1968544,721 - 549,5204,800
196973,581 - 77,7804,200 1969549,521 - 554,9205,400
197077,781 - 80,4272,647 1970554,921 - 560,9206,000
1971560,921 - 561,660740
total production: 79,527 total production:61,660

Month Key
0- Jan -1- Feb -2- Mar -3- Apr -4- May -5- Jun -6- Jul -7- Aug -8- Sep -9- Oct -10- Nov -11- Dec -12

CURTA I DATE CALCULATION FORMULA

CURTA I : YEAR = 1947 + ( SERIALNR / 80,000 ) x 24

Example: Serial Number = 15045
1947 + (15,045/80,000) x 24
1947 + .18806 x 24
1947 + 4.5135
1951.5135
12 x .5135 (now take the fractional part and convert to months)
6.1620 = early July
~ July 1951

Example: Serial Number = 58562
1947 + (59,862/80,000) x 24
1947 + .74828 x 24
1947 + 17.9586
1964.9586
12 x .9586 (now take the fractional part and convert to months)
11.5032 = Mid December
~ December 1964

CURTA II DATE CALCULATION FORMULA

CURTA II: YEAR = 1954 + ( (SERIALNR - 500,000) / 70,000 ) x 17

Example: Serial Number = 526699
1954 + ((526,699-500,000) / 70,000) x 17
1954 + (26,699 / 70,000) x 17
1954 + .3814 x 17
1954 + 6.4840
1960.4840
12 x .4840 (now take the fractional part and convert to months)
5.81 = late June
~ June 1960

Observations from Rick:

Notes and Original Formula From Erik van Dam:

I found somewhere that there are +/- 80000 Curta I and 60000 Curta II machines.

They were made from 1948 until +/- 1972 so if they have made the same number of machines every year, and I am sure they did not, you could use the next formulas to calculate the estimated year of production:

Curta I : YEAR = 1948 + ( SERIALNR / 80,000 ) * 24
Curta II: YEAR = 1948 + ( SERIALNR / 60,000 ) * 24

If the production numbers are correct you should be at least somewere in the right direction.

It is possible that there is a offset that has to substracted from the serial number first. So if anyone can tell the lowest and highest serial number for the Curta's I and II then I can perfect the formula!

Erik van Dam
0vdam03@flnet.nl

Notes from Reinmar Wochinz:

The production of the Curta I started with #1, the Curta II started with #500.000. The number of Curtas produced is approximately what Erik van Dam stated.

I myself have three Curtas at the moment:
#32.133 Curta I (open demonstration model)
#55.176 Curta I
#512.754 Curta II

Curtas I had in the last few years were
Curta I: #38.100, #54.788
Curta II: #515.417, #531.566

Reinmar Wochinz
Vienna - Austria
rwochinz@pop.tuwien.ac.at

Notes from Rutger Verbeek:

I have a very late (unused) Curta II, serial number 560608. I think that the last 5 digit are the production number.

Rutger Verbeek
Rutger.Verbeek@FernUni-Hagen.de


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