What is the difference between “error” & “mistake”?

A mistake is something that a person does willingly. For example, it would be a mistake to cross the street without looking both ways. However, the word error is usually used when there is a fault in something that is not controlled by the person. For example, you might find an error in a website, or you may receive an error message from a website which indicates that the error is most likely caused by the website itself, and not by the person or user. 

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There is overlap in the meaning. But while "error" simply means that something came out wrong, "mistake" implies that someone is to blame for it. As Dictionary.com defines it, a mistake is "an error in action, calculation, opinion, or judgment caused by poor reasoning, carelessness, insufficient knowledge, etc."