Wolfram|Alpha is the world’s first and only computational knowledge engine. Enter your question or calculation, and Wolfram|Alpha uses its computational power and ever growing collection of knowledge to compute the answer. Discover new information about the world, and integrate expert knowledge into any facet of your life.
The quest to make knowledge computable has a long and distinguished history. Indeed, when computers were first imagined, it was almost taken for granted that they would eventually have the kinds of question-answering capabilities that we now begin to see in Wolfram|Alpha.
Wolfram|Alpha Website: http://www.wolframalpha.com/