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baby calculator v1 perspective wm sm

Calculators today are so ubiquitous that you probably don’t give them a second thought.  It’s unlikely you are ever without one so long as you have your smart phone, tablet, laptop, desktop, etc. at hand.  You can buy battery operated calculators for a dollar at any number of stores and you will never even question their accuracy.  But it wasn’t always that way.

baby calculator v2 box wm sm

Calculating machines really started becoming practical business tools in the late 19th century.  However, only large banks, insurance companies, government agencies, etc. could afford them in the beginning.  But it wasn’t just accountants and bookkeepers in large organizations that had a use for these kinds of machines.  If you think about it, there are a large number of professions who use math as part of their job.  There would be, of course, merchants and salespeople, but also various tradesmen such as carpenters and plumbers.


newspaper ad from 1925

And thus we come to the Baby Calculator.  The Baby Calculator was marketed towards the home user for bills and shopping.  It was also marketed to folks who worked with numbers but for whom a full-size adding machine was impractical.  It seemed to be especially popular with individuals “who worked outside”.   It was also marketed towards small businesses and bookkeepers who needed a less expensive alternative to the larger adding/calculating machines then available.

1925 February Popular Mechanics ad wm sm

magazine ad from 1925

The Baby Calculator was a troncet-type adding machine made entirely of pressed steel.  When you purchased this item it would have included a leatherette case, instructions, some advertising material, and an aluminum stylus.  There were three versions sold throughout its history.  For versions 1 and 2 the differences were cosmetic as each was the same size and made from the same materials.  These measured 2.9375″ W x 5.75″ L x .4375″ H and weighed about 5 ounces.  Version 3, however, was made from pressed steel with a plastic back plate.  It weighed 6 ounces and measured 3.25″ W x 5.75″ x .3125″ H.  It also had a 9 digit display as opposed to a 7 digit display for versions 1 and 2.

The different versions were sold during the following time periods:

  • Version 1 – 1923 – September 1945
  • Version 2 – October 1945 – October 1947
  • Version 3 – November 1947 – until at least 1951

As I’ve mentioned in the past it should be understood that there would be overlap during when the different versions were sold.  While version 3 was available by November 1947 version 2 was still being sold also until stock ran out.

baby calculator v2 wm sm

version 2

baby calculator v3 wm sm

version 3

If you look at version 1 you can see at the top of the front it states “Patent Applied For”.  There never was a patent granted for this machine.  In my opinion this was a marketing ploy meant to give the impression that this was better than its competition.

While there were other troncet-type adders on the market during the time the Baby was sold, its main competition seemed to be the higher-quality Ve-Po-Ad (Vest Pocket Adder) Calculator.  There are a number of Baby Calculator ads stating that this is a less-expensive vest pocket adding machine.  The Ve-Po-Ad seemed to be a better seller and was offered by many office suppliers while the Baby Calculator was relegated mostly to mail order, traveling salesmen, and some retail outlets.

Consumers’ Research, Inc., the precursor organization to the Consumers Union which split from them during a labor dispute, for many decades issued a monthly bulletin where they tested various consumer goods.  In October 1949 they published an article titled “Small or Pocket Adding Machines” where they tested three different adding machines; the Addometer, the Tasco Arithmometer, and the Baby Calculator.  The Baby Calculator received a rating of “Not Recommended”, their lowest grade.  Following is their recommendation overview, but in the “Other Information” section below you can download the entire article.

CRB Oct 1949 Baby Rating wm sm

Oct 1949 Consumers’ Research Bulletin Recommendation. The Tasco Arithmometer received an even worse review.

newspaper ad from September 1945


magazine ad from October 1945

The company responsible for making and selling the Baby underwent a number of name changes in its history, although all of them were similar.

  • Baby Calculator Co – 1923
  • Baby Calculator Sales Co – 1925-1929
  • Baby Calculator Machine Co – 1924-1925, 1930-1932
  • Calculator Machine Co – (beginning in 1933 according to a trusted, but unsubstantiated, source) but proven from 1945-1950 and likely until it stopped being manufactured

newspaper ad from 1951

According to USPTO trademark 247,450 Harold S. Zewiske was doing business as the Baby Calculator Sales Company.  Mr. Zewiske died tragically in a plane crash in 1959 and while listed as being an editor for Vogue there was no mention of his connection with the Calculator Machine Company.  This tells me that either Mr. Zewiske was simply no longer engaged with that company or that it was out of business by 1959.  And it could be both.  However, with the latest ad that I can find being in 1951 it is my opinion that the Baby Calculator wouldn’t have been around for much longer than that.

1959 Zewiske Picture wm

Harold S. Zewiske

Other Information:


  1. The Baby Calculator Co (1923, July). Wanted-Male Help. Chicago Tribune, page 25
  2. Baby Calculator Sales Co (1925, February). advertisement. Popular Mechanics, page 174
  3. The Fair (1925, December). advertisement. Chicago Tribune, page 5
  4. Baby Calculator Machine Co (1930, June). advertisement. Popular Mechanics, page 139
  5. Storey-Kenworthy Co (1945, September). advertisement. Des-Moines Sunday Register, page 12-X
  6. Calculator Machine Co (1945, October), advertisement. The Pittsburgh Courier, page 3
  7. Calculator Machine Co (1947, November). advertisement. Popular Mechanics, page 340
  8. Editors (1949, October). Small or Pocket Adding Machines. Consumers’ Research Bulletin, pages 11-12
  9. Cox & Rich Stationers (1951, May). advertisement. San Mateo Times, page 7
  10. Editors (1959, February). Plane Crash Brings Grief to Many Here. Chicago Tribune, page 3

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