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.

About the author

A former editor at such publications as WIRED, Bloomberg Businessweek, and Fast Company, Belinda Lanks has also written for The New York Times Magazine, The New York Observer, Interior Design, and ARTnews.