BriCal patent drawing
BriCal patent drawing

3 Facts about BriCal

  • The BriCal was invented to quickly calculate pre-decimal British currency up to £500.
  • This popular British calculator came in many different configurations for different maximum results and currencies.
  • There are 12 pence in a shilling and 20 shilling in a pound, which make quick currency calculations difficult without a BriCal.

BriCal History

BriCal (after British Calculator) is a circular brass calculator, patented in 1905 by the engineer Herbert Dickinson and his wife, Mabel Dickinson. The adding machine was manufactured by the company British Calculators Ltd, London, from 1905 till the 1920s in different variants. The most common is a disk, with a diameter of 135 mm and thickness of 10 mm, weighing 450 g, put in a special case with velvet.

The exact time the company ended is unknown. It appears most of the BriCal calculating machines were manufactured in the first 10 to 20 years. Other sources cite manufacturing lasting until the 1950s.

Quick Facts

Herbert Dickinson, Mabel Dickinson
Original Use
Performing calculations in British currency
£3, 3 shillings
BriCal money calculator
The BriCal money calculator (Courtesy of Mr. John Wolf).

BriCal: How It Worked

This particular British calculator machine has three or more concentric brass discs which are drawn clockwise with the stylus to add pounds, shillings, and pence. Using the pin or stylus, one rotates the chain, until the wanted sums show in the window of the adding machine. Sums can be calculated in pre-decimal currency up to £500.

In order to clear the calculator, it surprising takes a few steps. It does seem odd to have to take so much time for a tool that is saving time calculating. One has to notice where a red dot is on some of the teeth and then pull those teeth to zero using the stylus. Next, you have to do the same for the other two rings that are left. Finally, the counter wheel must be reset to zero by using the tiny knob. If all these steps are preformed, a user can move on to the next computation.

These are just the basic instructions for the original BriCal. The machine was manufactured in a surprising number of variants for its apparently short production time.

Some BriCal machines were manufactured to work with different currencies. Others could calculate sums over £500. Still others were designed in different sizes and colors.

BriCal: Historical Significance

According to the BriCal money calculating machine instruction booklet, this machine is capable of calculating British currency six times as fast as mental addition. While the machine appears to have been popular during its time, it was discontinued sometime in the 20th century. Some report it was only in production for approximately 10 to 20 years, with manufacturing ceasing some time before 1925. Others claim it was manufactured until 1950.

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BriCal Explained – Everything You Need To Know FAQs (Frequently Asked Questions) 

When was the BriCal invented?

The BriCal British currency calculator was invented and patented in 1905.

What is a BriCal?

A BriCal is designed to quickly calculate pre-decimal British currency. It’s reputed to make calculations at least six times faster than mental addition.

Who invented the BriCal?

Herbert Dickinson, an engineer, patented the BriCal with his wife, Mabel Dickinson.

How does the BriCal work?

The BriCal adding machine uses several brass discs and a stylus. The user simply rotates one of the three chains to the correct sum of pounds, shillings, and pence to find the total sum.

Can you use the BriCal for American currency?

The BriCal was originally used only for British currency calculations. Many variants of the calculating machine were made and there are reports that some BriCal machines were designed to calculate American dollars.

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