Vintage British Calculators



The Muldivo Calculating Machine Co. Ltd., "Specialists in Calculating Equipment since1912", was a distributor of mechanical and electronic calculators from many companies, including Guy's, IME, Madas, Precisa, Thales, Walther, and also manufactured some models.

Many of the calculators distributed by Muldivo retained their original names, but the ones below were re-badged with the Muldivo name.

Known models under the Muldivo name:

See the bottom of this page for a brief history of Muldivo.

Muldivo (no model number)

Unknown model

Muldivo (no model number)

Pinwheel calculator with 9-digit setting register, 8-digit revolutions counter, 13-digit accumulator register.

This is probably the earliest Muldivo model, and is marked "Made in France".

In Martin, "The Calculating Machines" (M.I.T. reprint), p348, are details of the "Muldovo" (sic) which was introduced in 1924.  The accompanying picture shows this model and says "The Muldovo is a miniature pinwheel calculator of French origin. the name of the manufacturer is unknown to us".

This model is to be identical to the picture of the "Chateau" calculator, on page 164 of Martin, where it says "the owners of the factory are the Chateau Bothers [ie. Chateau Freres], [in] Paris. ... It became better known under the name Dactyle, ... It was offered for sale at various places outside of France, ..."

Allan Easton, in the brief history of Muldivo, at the bottom of this page, confirms that early Muldivo machines were manufactured by the Chateau Freres company.

Muldivo AE

Muldivo AE

Pinwheel calculator with 10-digit setting register, 8-digit revolutions counter, 13-digit accumulator register.

This is of similar style to the model DER shown below, and was probably again made for Muldivo by Thaleswerk in Germany.

Muldivo DER

Muldivo DER

Muldivo DER

The machine is marked on the back - "Thaleswerk GmbH Rechanmaschinen-Spezialfabrik, alt/Baden, Germany."

Muldivo were the british importers and distributors.

From Martin, "The Calculating Machines", p254, this can be identified as based on a Thales Model D.

12-digit setting register, 10-digit revolutions counter, 18-digit accumulator register.

Made in 1930s-1940s.

395 mm x 145 mm x 120 mm (16" x 6" x 5"), 9 1/2 Kg (21 lbs.).


Calculators from Muldivo with a similar look include the models AE (above), BE and CER.

Inside Muldivo DER

With covers removed.

This is an Odhner-type pin-wheel machine (see the Odhner calculator in the Mechanical Calculators section of the Vintage Calculators site).

Basic method of operation - When one of the setting levers is moved to a number then that number of pins is raised on the corresponding pin-wheel (ie. moving a lever to '7' raises 7 pins).

Turning the handle rotates all the pin-wheels.  The raised pins act as gear teeth and advance the individual accumulator wheels (with numbers at bottom right) by the number of pins, so adding the set number to the accumulator.

Close up showing the pin wheels with the number of pins raised on each wheel depending on the number set by each lever (from left to right 000123456789).

Inside close-up Muldivo DER

Multiplication is fairly straight forward since the handle can be turned several time quickly to add the same number to the accumulator.  The numbered wheels at bottom left keep a record of the turning of the handles.

Moving to the next decade involves pressing the appropriate lever at the front.

The big wing nuts are for clearing the accumulator register and the revolutions counter.  On the models of this series the setting levers are cleared by moving the lower lever on the right upwards.

For information on performing the basic arithmetic operations see Operating a Pinwheel Calculator in the "Collecting Calculators" section of the Vintage Calculators site.

For details of the pinwheel mechanism click here.

Muldivo Mentor

Muldivo Mentor

Muldivo Mentor

Made in Germany by Walther (model WSR 160).

285 mm x 155 mm x 136 mm (11.25" x 6.1" x 5.4").

An Odhner-type rotary pin-wheel machine with 10-decades setting register, 8-decades revolution counter, 16-decades accumulator register.

Made 1960s.

Muldivo were the British importers and distributors.

This machine is fitted with a "back transfer" mechanism, operated by the reddish-brown lever at top right.  This transfers the number in the result register, centre right, to the setting register, centre, which can be very useful in chain calculations.

Operating Manual
Here is the Operating Manual of the Muldivo Mentor in pdf format.

This machine is covered in more detail in the featured Mechanical Calculators section on the Vintage Calculators site.

In the 1960s this model was promoted for use by schools in teaching the basics of mathematics as described in Muldivo Calculators for Schools (pdf format).

Muldivo were also importers to the UK and distributors of some early electronic calculators, such as the IME 84rc, but apparently did not put their own name on any.



A brief history of Muldivo

Allan Easton, a son of Henri Ebstein, the founder of Muldivo, has kindly provided the following information:

Muldivo, founded in 1912, was based at 49, Queen Victoria Street, London EC4, at least from the mid-1920s until 1951 or 1952 when it moved to a new building Dorset House, Salisbury Square, London, EC4, off Fleet Street.  However, this building soon became too small and a further move was made to Banner Street, London EC1, just outside the City limits in about 1960.  The company stayed here until its demise in 1971 due to the cheap electronic calculator revolution.

The first machines sold were made by Chateau Freres, a substantial scientific instrument maker in the French Jura.

Muldivo bought Guy's Calculating Machines Ltd. from the brothers Guy in about 1939 and we made a Thales-type machine there after the War.  I joined Guy's on de-mob in 1946 and stayed till we sold it in about 1969, by then it had become a general precision sub-contracting works and had moved to Witham, Essex, in 1965.

The IME was a superb electronic calculator for its time.  I think ANITA came out first, but they were not in the same street as our Italian machine, thanks to a brilliant engineer, around whom IME was created by the vast Montecatini-Edison concern.  When he left, they went right down and eventually closed.



The Times of April 14, 1972, reported:[1] "Fonadeck International, the Birmingham-based business equipment company, has moved into the electronic calculator and mini-computer field by purchasing Muldivo, of London for an undisclosed sum.
Mr Jacqes Chapman, Fonadeck's chairman and managing director, said "The Muldivo equipment complements our range and its sales will increase our turnover by a further £1.25m a year.""



  1. "Fonadeck Purchase", The Times, April 14, 1972.

Vintage British Calculators

Text & photographs copyright, except where stated otherwise, © Nigel Tout 2000-2024.