Surprisingly Functional: The World's First Gesture-Based Calculator

The Rechner iPhone app translates mathematical functions into finger swipes and yields a 200% increase in efficiency.

Last week, iTunes became home to a historical first. This time, in the form of an ingenious app that turns an iPhone into a gesture-based calculator that replaces the most common mathematical function keys with finger swipes.

Rechner is the work of Berger & Föhr, a two-man studio based in Boulder, Colorado. "As with the majority of our internal projects, we were generally dissatisfied with the current offering," says Lucian Föhr, who conceived the app with his partner Todd Berger. "We recently purchased a beautifully designed calculator only to discover that it was functionally inept. We were left with the option of hunting down another or building our own." They chose the latter, opting to create an app that didn’t kowtow the physical constraints of a traditional device. The entire process, Föhr says, took 16 days, from the initial idea to Apple approving the app on March 14:

We designed the app the evening of February 28th. It took us about 45 minutes. The following day, we approached Keiran Flanigan of Rage Digital to see if a.) he felt the app was valuable and b.) if he would be interested in partnering on the development. He answered with a resounding yes to both. We sent our design files to Keiran and went to lunch, where we came up with the name.

The name is Rechner, a nod to Braun and their German roots ("rechner" roughly translates into "calculator" in German, though it’s used more generally to refer to any "computer").

So how does it work? Berger and Föhr removed all the function buttons from the interface and assigned four basic gestures to the most frequently used: Left to right for addition, right to left for subtraction, and bottom to top to calculate; swiping with two fingers acts as the clear key. All the other functions are in a hidden drawer, which can be opened by swiping down. The response has been overwhelmingly positive, the duo says, and they’re already working on an updated version, which we hope includes separate gestures—perhaps diagonal swipes—for multiplication and division.

The designers claim that the Rechner calculator increases efficiency by 200%. Asked how they arrived at that figure, Föhr responded: "We didn’t. We’re not very good at math, hence the desire to design a new, better calculator."

Buy the $.99 app here.

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  • Thom McKiernan

    It certainly does seem to be the only gesture based calculator app on any OS but the Casio AT-550 thought of it first, and did a better job of it.
    Why not make a simple version that uses OCR on a plain screen?The Inkulator app does that for Windows 8 

  • BakariC

    Cool design. I downloaded it just for that. However, if you don't use it on a regular basis, you might tend to to forget the gestures, especially multiplication and division. 

  • ptamzz

    Why does people always try to use something like 'the first' to describe something even when it is not!

  • Renato Castilho

    harder to use with one hand —a must IMO— than the classic design #beautifulfail

  • Steve

    I am not really sure how this is more efficient when a single button press of the addition function would be more economical than a press and swipe for the addition function.

  • Steve

     I will say though that it is novel and will promote discussion which is always good.

  • Lanea

    There is an app for kids called Math Samurai that uses gestures in similar fashion.

  • Vikingosegundo

    Designers would argue, it works better than a traditional button-based interface. Mathematicians must argue it is not working at all: floating point always result in Zero, operator precedence is unknown (5+5*2 results in 20 but should be 15)

  • J. Adam Moore

    Uhh, I hate to be the one to tell you this, but the abacus was the first gesture-based calculator. :)

  • saurabhr8here

    There is a lot of feedback in the App store that it needs a lot of work to clear out the bugs. Hope the developers are reading customer feedback.