A kickass, open-source calculator that lets you do calculations and unit conversions naturally, with features like:

gUnit is described as 'Covers every possible conversion need you may encounter. You can figure out how much a meal might cost you in US Dollars while you're traveling in Switzerland or how many miles you'd have to run to the bus stop when everything around you is in kilometers' and is a Calculator in the education & reference category. There are more than 50 alternatives to gUnit for a variety of platforms, including Android, iPhone, Web-based, iPad and Linux apps. The best gUnit alternative is Converter NOW, which is both free and Open Source. Other great apps like gUnit are Numi, Calculator++, XE.com and Currencies.
A kickass, open-source calculator that lets you do calculations and unit conversions naturally, with features like:

A Chrome extension that gives you a ticker for the current Bitcoin price, a price graph, a currency converter and price desktop notifications. Supports many cryptocurrencies, precious metals and fiat currencies including Linden dollars (Second Life currency).


multiConvert is a free, open-source unit converter software with real-time conversion result.





Elk is a super fast way to convert currencies, interacting with set values across increments accessed using simple swipes. No need to enter values with a keypad, it lets you just swipe your way to the value you need.




Power calculator for Android. Has Calculus, Algebra, 2D/3D Graphing and other features.




Valuta+ is a super simple & free currency converter. The interface is fast and makes you convert exchange rates very easily. This app have more than 160+ currencies for you and is always updated.




Currency Converter from Yahoo! Finance. Find the latest currency exchange rates and convert all major world currencies with our currency converter.

As the name suggests,
Universal Currency Converter is a simple currency converter tailored to the users in Asia Pacific region.
It also enables you to see the commodities prices of:
Gold,
Silver
Platinum.


Unit Wolf is a unit conversion program created for quick and reliable conversions. Enter entire equations or just simple numbers. Convert between 170 currencies or easily add different units together. Supports Length, Temperature, Pressure, Digital Storage, Mass, Speed, Volume...


ConvertPad is a fully featured unit converter offering various unit conversions in a Android phone. It is the units converter made specifically to match the look and feel of the Android. With all of the conversions that ConvertPad can perform, It is especially useful for...



Calculator is a simple 4 function calculator, with a panel that has more advanced functions when you need them. It includes history, real time graphing, base conversion, and more. It also comes with a lockscreen widget, a floating calculator, and a wear app so you can use...