Jaap's Mechanical Calculators Page


The Denominator

The Denominator Company
My Denominator Lab Counter

The Denominator Company

The Denominator Adding Machine Company was founded in Brooklyn, New York, in 1914. The first machine they produced had 11 three-digit counters, one for each denomination of US currency from $20 to 1 cent, and a single reset mechanism. It was designed by William A. Cook and Joseph Levine, and they filed for a patent in 1921 which was granted in 1923. Somewhere around 1930-1935 the company moved to Woodbury, Connecticut, (though a Brooklyn address was kept on for many years) and shortened their name to The Denominator Company. Other models were produced - single counters, multiple counters of various sizes, multiple counters with a totaliser, including those which lock when the total reaches a multiple of 100.

The company still exists, and still produces similar types of counters though they are now mostly made of plastic so they are much less heavy.

My Denominator Lab Counter

This machine has five independent 3-digit counters, and a totaliser. There are five buttons, one for each counter, and when you press one of them 1 is added to its counter. The button also pushes down a bar that is connected to where the button of the totaliser would be, so that every button press also increments the totaliser. The Denominator Company still sells similar types of machines which they call Lab Counters, which can be used when running an experiment with many samples that can have up to 5 different outcomes. Clips on the front of the counters allow you to insert a label to mark what each counter is being used for.

Each counter unit has a date printed on the bottom. The most legible one is Oct 29 '48, so presumably it was manufactured in 1948 or shortly thereafter. However, the decal on the front uses a logo that according to its trademark application was first used in 1950. This is probably the last generation of fully metal counters they made since the patent filed in 1949 shows their new design that uses a plastic casing. The serial number 25029 is stamped under the edge of the case.

The Denominator
The Denominator, button pressed 1
The Denominator, button pressed 2
The Denominator, logo
The Denominator, label clips
The Denominator, reset nut
The Denominator, rear
The Denominator, bottom
The Denominator, bottom, date close-up
The Denominator, bottom, serial number

To reset the counters, turn the wing nut until all the digits read zero. The wing nut on the left clears the five counters simultaneously, and the wing nut on the right clears only the totaliser. Turning the wing nuts the wrong way has no effect, though it can mean that you have to turn it almost two whole revolutions to clear the counters next time.

The Denominator, interior, front
The Denominator, interior, back 1
The Denominator, interior, back 2
The Denominator, interior, totaliser

The totaliser has a locking mechanism, but it has been disabled. There should be a small pin in the hundreds wheel of the totaliser which would slide the locking bar in place when the wheel turns from 0 to 1. At this point the total is 100, so the numbers in the other counters can be read as percentages of the total. This model does not seem to have had any release mechanism for the lock other than resetting the totaliser counter. I found a patent for such a release mechanism that was filed in 1951.

The machine is in reasonable condition. Some of the wrinkle paint is flaking off, the window of the totaliser counter has been replaced with a yellower plastic, and a spring is broken that should push the totaliser bar back up again after a button press.



I have looked through online archives and found very few mentions of the Denominator Company. I found no advertisements, a few copyright entries, and one profile in a fraternity magazine.

1924 The American Digest Of Business Machines
1925 Ernst Martin
1952 Catalog of Copyright Entries Commercial Prints and Labels
1953 Catalog of Copyright Entries Commercial Prints and Labels
1954-05 Sigma Phi Epsilon Journal
1959 Official gazette of the United States Patent Office


PatentFiling datePublish dateNameDescription
US 1,444,58609-03-192106-02-1923William A. Cook and Joseph LevineDenominating Apparatus.
US 2,175,62119-08-193610-10-1939Anton van VeenTotalizer for counting machines.
US 2,572,78402-03-194923-10-1951Anton van VeenHand-operated Counter or tally.
US 2,762,56708-10-195111-09-1956Anton van VeenTotalizer counter having means for stopping operation on reaching a predetermined number.


The Denominator Company home page.
Payroll Counter or Denominator from the 1920s, in the National Museum of American History.
Rechenmaschinen illustrated also shows the original Denominator money counter.
Hand Counter for Tallying from the 1950s, in the MoMA's collection on Architecture and Design.

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