John Wolff's Web Museum

Comptometers - An Operator's Story

Contributed by Mrs Lorraine Adamson, Newcastle, Australia


Burroughs calculator

The Burroughs Calculator or Comptometer was new to me when I commenced training in May 1960. My mother had seen an advertisement in the local newspaper (The Newcastle Morning Herald) which stated that it was a 'machine that could perform maths calculations.' Although I loved maths I didn't realise the amount of enjoyment that I would get through employment, while working with these machines. I had just turned fifteen when I commenced the course in May 1960.

The Burroughs Training Centre was situated in the suburb of Hamilton, near the corner of Hunter St and Tudor St. The training course went for three months, and we were assured that employment would be found for us at the end.

There were about 15 manual machines and 2 electric ones in the training room. We were all taught on the manual ones and it took quite an effort to get up your speed as the keys were very sluggish and hard to press. Once I had learnt all facets of the machine, I progressed to the electric. What a breeze! It was so easy to press the keys; my hands seemed to glide over them.

The Comptometer was also taught as part of a Business Course at Tighes Hill Technical College. My younger sister did her training there in 1970.


True to their word, I was found employment in August that year at Rylands Wire Rope Works. The General Office there was as big as a large hall. All clerical departments were there and down one side was the Comptometer Pool. Similar to a typing pool, except calculations were worked out for all the departments, checked and returned to the relevant department. I worked there for about two years.

In 1963 I went to work at Newbold General Refractories. The office there was different to Rylands as each department had its own Comptometrist working for them. My older sister had also learnt the comptometer and was working there when I first started, and later my younger sister also commenced. My time there was spent mainly in the Production and Cost Departments. This gave me a variety of clerical and calculating work. I became a team member of the department and had different responsibilities to those at Rylands. I loved working at both places, probably because they were so different from each other.


Rylands Wire Rope Works was situated on the site of the BHP steel works, which was established in 1915 and was by far the largest in Australia. When I look back to this era, it is in stark contrast to what is there today. The BHP whistle would blow at the start and end of each shift. Literally thousands of people (mainly men) would come pouring out of all the sites, buses would be ready to pick up people and take them to all parts of Newcastle, Lake Macquarie and parts of the Hunter Valley. Push bikes and cars were everywhere. Even the radio would sound the whistle at eight o'clock and say "It's eight o'clock at BHP". The car park just outside the Ingall Street gates was always full day and night. Newcastle was most certainly an industrial "Steel City" and the smell and smog could be seen and smelt from the outskirts of the city.

Newbolds was a smaller business than Rylands and was situated in Mayfield West, backing on to Commonwealth Steel Company site. Both Rylands and Newbolds were bought out by BHP.

BHP finally closed its doors in in Newcastle in 1999. The car park is now a self storage area, many of the offices stand empty and derelict, and most workshops are being demolished. The end of an era had come. The positives are that the pollution has gone. Tourism is on the rise and Newcastle has changed from being the Steel City to a tourist area and large coal exporter. It is the gateway to the Hunter Valley.


The skills I learnt on the comptometer opened doors when I travelled to Sydney and Melbourne for a year. There were always casual jobs available in both areas. I also worked on different machines to the one I was trained on, but the skills I had, enabled me to use each machine.

In 1974-75 my younger sister travelled to England and worked at Kelvinators. Their set up was similar to Rylands but they had a separate office (probably so they wouldn't get distracted) and did calcs for all the departments. The friendships she made still lasts today.

Decimal Currency and beyond

Australia's conversion from the British to the Metric system of measurement began with the introduction of decimal currency in 1966.

I think to some degree the art was taken out of the comptometer when we converted to decimal currency and from yards to metres. No longer did we convert in our minds as we were calculating money and yards. It was all there in front of us, much easier to do. We went from multiples of 12 to 10.

Some comptometers were converted to decimal units by re-arranging the keytops, so that the last two whole numbers showed decimals to two places. Many didn't bother with conversion, as the operators never really looked at the keys, and the decimal point indicators were always set to the correct position. They just didn't use the shillings and pence columns (the 3 right hand columns) any more.

The change to the metric system was also the beginning of the end of the comptometer. By the early 1970s the small ten-key table calculators and adding machines started to appear in businesses. You didn't need to be trained in how to use them. Over the next ten to fifteen years they were appearing everywhere, while comptometers were being phased out.

I was working at Newbolds when a couple of the departments purchased the ten-key machines. One chap brought down a lengthy addition when they first got them, and unbeknown to me his mate in their department started adding the same sum when I did. I didn't know it was a race and they were having a bet as to who was faster. I added it up and checked it before he had totalled his.

For the last 22 years I have changed to computers, working in schools in the Newcastle area. My younger sister owns her own business and my older sister does research on genealogy. We have all changed to computers with the times, but have fond memories of the Burroughs Comptometer.


Calculating on the Comptometer

The Keyboard

Burroughs calculator

The Comptometer had nine rows of whole numbers on the left-hand side. The two rows of brown keys towards the right-hand side were for addition of shillings (1 to 19). The last full row of white keys was for addition of pennies (1 to 11), with the 10 and 11 pence at the top of the last row. The three separated keys were for halfpennies and farthings. The row of small buttons at the bottom of the keyboard was used for subtraction.

The result appeared in the windows below the keyboard. The decimal point bar next to the windows had four indicators which could be moved to any position you wanted. The result was cleared by pressing the bar at the right of the keyboard.

The comptometer will add with every press of a key. When 9 is pressed once the answer is 9. Pressing again shows 18. Pressing 7 times shows 63 (ie, 9 x 7). Whether adding, subtracting, multiplying or dividing, this is the basis for all calculations.

Types of calculations

Wages, costing, production, purchases, budgets, etc, were all calculated with the Comptometer. Some of the calculations included:

Pounds, shillings and pence were written with the symbols £.s.d. For example, £1/15/6½ was one pound, fifteen shillings, and six pence halfpenny. When multiplying, the shillings and pence were converted to a decimal of a pound before commencing. While doing any calculations you were always working smaller calculations out in your mind.


When adding, your fingers don't move above the row of 5s. Therefore if you were adding 6789 to a figure, you would use your left hand for the thousand column and your right hand for the hundreds, tens and units. You would enter 3 twice for 6 thousand, 3 and 4 for 7 hundreds, 4 and 4 for 8 tens, 3 and 3 and 3 (or 5 and 4) for 9 units. The reason for this was for speed. It was like touch typing - you didn't look at the machine.


To subtract you had to use the small numbers on the keys, and the small buttons at the bottom of the keyboard.

For example, to calculate 1578 - 856:


Multiplying whole numbers commences at the left hand side of the machine. You will notice that there are nine rows of whole numbers, but where the answer comes up there are ten windows. This is logical, for if you multiply 9x9, starting at the left hand side of the machine, you will need an extra place on the left to show the answer 81. To multiply 9x9 you would just press the 9 in the first column nine times.

A glance at bigger calculations, eg 1234 x 998 would tell you to hold (ie, position your fingers to) the 998, in the first three columns. You hold the number with the largest digits so that you don't have to press the keys as often. Press once, and move one place to the right. Press twice, move over; press three times, move over; press four times. As there are 7 digits in the total sum, the decimal point is placed after the seventh number column counting from the left.

Multiplying pre-decimal money was more involved as the shillings and pence had to be brought to a decimal. It wasn't long before I could remember all the decimals to bring shillings and pence to a decimal of one pound - one penny was 0.0041666, £1/15/6 (one pound fifteen shillings and six pence) was 1.775. Once dollars and cents came in there were no conversions necessary - £1/15/6 would just read $3.55.

Calculations in other units were done with conversion tables. When I did the course in 1960 we were given a set of cards that we could use in our work environment. They included things like weights as decimals of a ton, or days expressed in decimals of a year. I still have most of these cards.


This was the hardest calculation to master. There were three rules:

  1. Equal the stroke wheel
  2. Reduce the remainder
  3. Move over - repeat the three rules

These three rules confused everyone in the training room when I was learning, but once you got the hang of it, it all made sense.

For an example, let's divide 1050 by 75.

Starting from the left hand side of the machine enter 1050, set the decimal point, then move it back two places because you are dividing by 75.

Use the small numbers on the keys, less One. That is, you will hold 74 looking at the small numbers (25 on the big keys) but remember that you are dividing by 75.

Now follow the three rules:

  1. Equal the stroke wheel. In each part of the calculation the stroke wheel is the answer wheel to the left of where you will hold the 74. Hold the 74 directly above the 10 you have entered. The answer window to the left is a 0, so you are already equal to the stroke wheel.
  2. Reduce the remainder. Still hold the 74 in the same position. Because 75 is larger than 10 you cannot reduce it.
  3. Move over. The 74 is moved one place to the right.
  4. Equal the stroke wheel. The stroke wheel now has a 1 in it. Press 74 once. The 1 didn't change, so you have equalled the stroke wheel. You should see 1300 in the answer.
  5. Reduce the remainder. Still hold the 74 in the same position. Because 75 is larger than the corresponding 30 in the result windows you cannot reduce it.
  6. Move over. The 74 is moved one place to the right.
  7. Equal the stroke wheel. This now has a three in it, so you need to press three times. You should now have 1375 in the answer windows. (If the 3 changed during this part to a 4 then you would need to press again).
  8. Reduce the remainder. Because 75 is equal to the matching 75 in the remainder, you press once to reduce it. (If you were dividing by a smaller number you might need to press multiple times, until you can't go any further).
  9. The answer should now show 1400 - that is, 1050 divided by 75 = 14.00

When dividing by a figure with a 9 in it, eg 99, you will notice that there is no 9 in the small numbers. You still need to take one number off, which makes 98. Because there are no nines, you hold nothing in the tens column and eight in the units, but remember that the Stroke Wheel is in the hundreds column.

Original text Copyright © Lorraine Adamson 2007.
Last Updated: 4 November 2007

Back to:    Home    Calculating Machines    Comptometers and key-driven calculators    The Comptometer operator