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This calculator is the best in the world and a design classic!

Written by Simon Leadbetter, published on

This is the best calculator in the world! Why? We explore what a UX designer (or any designer for that matter) can learn from this everyday object. 2 plus 2 is 4, now that’s quick maths.

Aurora DT210 calculator on a pink background

I love this calculator. It is a masterpiece, both in its design and usability.

When something just works, it is easy to overlook its brilliance, so we are going to take a moment to stop and analyse why this calculator was (perhaps inadvertently) designed to be the best in the world. Before we begin…

Have you ever wondered about the difference between the C and the CE button on a calculator?

The C (clear) button will clear all input to the calculator. The CE (clear entry) button clears the most recent entry. This is great if you made a mistake in a computation to work out the mass of the universe as I did once.

Okay. Let’s take a look at the Aurora DT210 in more detail.

It is durable

There was no planned obsolescence when they designed this product. I have probably owned it for 25+ years and it is still going strong. The combination of its simple design, quality material choice and the solar power means there has been no need to change a battery — not once.

If you drop your phone, there is a sudden rush of panic as you know it is going to cost a fortune to replace the screen. Ha, that’s not the case with this calculator. I bet this calculator could be on a Virgin Galactic flight with Richard Branson and it would still return in one piece.

It was designed for me

I was never good at mathematics. Working out a percentage, although simple, was strangely a challenge for me. Divide what you have by what it is, times 100 or something like that. No need with this calculator as it has a percentage button. How good is that!

It is so simple, even my grandma would understand how to use it

There are just enough buttons and none with weird symbols. There is no need for advanced functions when all you need is to do simple calculations.

It has great affordance (affordances are properties of objects which show users the actions they can take). Simply put, you know they are buttons that need pushing.

Practical, accessible design

There are so many things to learn from the design of this humble calculator:

  • The buttons are grouped perfectly. Numbers on the left, operators on the right with basic memory functions in a row above
  • I love the fact the equals button is the last button on the bottom-right. When doing speed calculations (yes, I am capable of that), it is instinctive to find this button due to its considered placement
  • Have you noticed the larger addition button? The button that is used most is easiest to press
  • The more observant will have noticed the spacing between buttons. There is enough to avoid the accidental pressing of the adjacent button. This is touchscreen interaction design, done decades before touchscreens were a thing
  • The light grey colour of the base provide high contrast for the coloured buttons
  • For those with colour blindness, there is very little to get mixed up. No red/green confusion with this user interface. Just a single red button for the power on button (which doubles up as the clear function) making it extremely easy to locate. Cleverly, red is the colour universally associated with a warning which is perfect for the clear function. The only other colour used by this design is blue for the memory buttons that help identify them, but does not overpower the dark grey colour
  • No icons, but clear text labels. Off and On. Not a power symbol in sight
  • The slight tilt of the display makes for easier reading when the calculator is placed on a flat surface
  • The large digit LCD display is clear to read

Micro design features

I am also a fan of the micro features of this calculator. The insetting of the Off and On buttons indicates that these buttons are somehow different to the rest, as they are grouped together.

On the reverse, the moulded plastic has grips. Yes, grips. No slippy-slidey on the desk.

The display

Although it has never been a problem for me, it could be argued that the display could be improved with modern technology, but it would undoubtedly increase the price. I guess this is the trade-off in having a low-powered display that prioritises longevity over ultra-clarity. For the little contact time most users will have with the calculator, the higher price point would be an unnecessary expense.

Importantly, this calculator still allows you to create words from numbers…

Calculator spelling the word Shell Oil

And for the immature among us…

Calculator spelling the word boobies

Rounding things up

Apple, Dyson and Audi are some of the brands that are typically associated with great product design, but they were not responsible for this marvel. Neither was Dieter Rams or Jony Ive. It was a Taiwanese company called Aurora and they, along with the original designer, deserve the same accolade as these big companies for this amazing calculator. It has outlasted all my mobile phone and still going strong.

The heuristics and highly considered design decisions made by designer are easily transferable to designing a website. Colour choice, colour contrast, button labelling, button grouping, hit area target, uncomplicated operation with minimal learning curve, easy navigation, avoidance of paradox of choice (limited functionality) and human-centred design (larger addition button, percentage button) are all factors that need to be considered when designing a website.

So ask yourself ‘does my user need the equivalent to the Aurora DT210 percentage button’ when you work on your next project.

At Scaramanga, we are a bit strange. We see beauty in things others would simply gloss over and we apply this deep thinking to every project we undertake. If you want to work with a team that sees beauty in a humble calculator and gets excited by its accessibility, then we are your guys and girls.

If you have a website project that needs the Aurora touch, then get in touch.

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