Math done simply. Designed in the Swiss style, Sumhold is a calculator that instantly calculates and stores numbers with a fiercely reductive interface and simple swipe gesture.

This is the result of a beautifully developed iPhone app by Chad Voss, an independent interaction designer from Seattle. Sumhold, featuring an attractive minimalist design, makes complex calculations and number storage simple. Sumhold is made for those everyday calculations (e.g. groceries and budgets) when you need to do simple arithmetic while keeping track of previous calculations and results.

Unlike most basic calculators, Sumhold keeps a running tally of your current calculation at the top and, when calculations become complex, automatically inserts parentheses to keep everything clearly readable. There is no need for an "=" button because it calculates as you type.

When a calculation is complete and you need to store the result for later, you simply drag it down toward the keypad into Sumhold's scratch-line to make a temporary button.

Having downloaded this app myself, I must say that it is a joy to use. Incredibly simple both in aesthetic and function. Currently available on the iTunes store.